This is a list of countries by IPv4 address allocation.
The Internet Assigned Numbers Authority (IANA) distributes large blocks of addresses to regional Internet registries (RIRs), which then assign them to national Internet registries and local Internet registries within their respective service regions. [1] While IPv4 allows for a theoretical maximum of 232 addresses (approximately 4.3 billion), the number available for public use is smaller due to reserved blocks for private and special purposes. [2]
# | Location | IP addresses | % | Population | IP addresses |
---|---|---|---|---|---|
(total world allocation) | 3,686,475,740 | 100 | 8,091,734,930 | 456 | |
1 | ![]() | 1,611,297,420 | 43.71 | 343,477,335 | 4,691 |
2 | ![]() | 343,125,576 | 9.31 | 1,422,584,933 | 241 |
3 | ![]() | 189,145,768 | 5.13 | 124,370,947 | 1,521 |
4 | ![]() | 134,054,832 | 3.64 | 68,682,962 | 1,952 |
5 | ![]() | 124,185,676 | 3.37 | 84,548,231 | 1,469 |
6 | ![]() | 112,495,296 | 3.05 | 51,748,739 | 2,174 |
7 | ![]() | 87,096,200 | 2.36 | 211,140,729 | 413 |
8 | ![]() | 82,053,600 | 2.23 | 66,438,822 | 1,235 |
9 | ![]() | 67,921,556 | 1.84 | 39,299,105 | 1,728 |
10 | ![]() | 54,020,088 | 1.47 | 59,499,453 | 908 |
11 | ![]() | 48,112,552 | 1.31 | 18,092,524 | 2,659 |
12 | ![]() | 46,444,728 | 1.26 | 26,451,124 | 1,756 |
13 | ![]() | 44,859,860 | 1.22 | 145,440,500 | 308 |
14 | ![]() | 41,624,148 | 1.13 | 1,438,069,596 | 29 |
15 | ![]() | 35,715,484 | 0.97 | 23,317,145 | 1,532 |
16 | ![]() | 32,317,160 | 0.88 | 47,911,579 | 675 |
17 | ![]() | 31,070,628 | 0.84 | 10,551,494 | 2,945 |
18 | ![]() | 28,989,412 | 0.79 | 129,739,759 | 223 |
19 | ![]() | 27,077,224 | 0.73 | 63,212,384 | 428 |
20 | ![]() | 26,590,876 | 0.72 | 5,789,090 | 4,593 |
21 | ![]() | 25,433,100 | 0.69 | 8,870,561 | 2,867 |
22 | ![]() | 24,147,252 | 0.66 | 114,535,772 | 211 |
23 | ![]() | 19,971,716 | 0.54 | 38,762,844 | 515 |
24 | ![]() | 19,445,316 | 0.53 | 45,538,401 | 427 |
25 | ![]() | 18,984,372 | 0.51 | 281,190,067 | 68 |
26 | ![]() | 17,373,224 | 0.47 | 52,321,152 | 332 |
27 | ![]() | 16,702,740 | 0.45 | 87,270,501 | 191 |
28 | ![]() | 16,411,204 | 0.45 | 100,352,192 | 164 |
29 | ![]() | 15,545,680 | 0.42 | 5,519,167 | 2,817 |
30 | ![]() | 13,709,400 | 0.37 | 5,601,185 | 2,448 |
![]() | 13,155,600 | 0.36 | 7,442,734 | 1,768 | |
31 | ![]() | 12,353,044 | 0.34 | 11,712,893 | 1,055 |
32 | ![]() | 12,271,580 | 0.33 | 37,712,505 | 325 |
33 | ![]() | 11,968,444 | 0.32 | 5,948,136 | 2,012 |
34 | ![]() | 11,297,028 | 0.31 | 90,608,707 | 125 |
35 | ![]() | 11,235,160 | 0.30 | 9,130,429 | 1,231 |
36 | ![]() | 11,105,124 | 0.30 | 5,196,630 | 2,137 |
37 | ![]() | 10,720,264 | 0.29 | 33,264,292 | 322 |
38 | ![]() | 10,038,880 | 0.27 | 19,658,835 | 511 |
39 | ![]() | 9,521,764 | 0.26 | 10,809,716 | 881 |
40 | ![]() | 9,265,812 | 0.25 | 37,732,836 | 246 |
41 | ![]() | 9,189,444 | 0.25 | 71,702,435 | 128 |
42 | ![]() | 7,987,856 | 0.22 | 9,256,314 | 863 |
43 | ![]() | 7,876,420 | 0.21 | 12,200,431 | 646 |
44 | ![]() | 7,756,600 | 0.21 | 19,118,479 | 406 |
45 | ![]() | 7,471,836 | 0.20 | 127,951 | 58,396 |
46 | ![]() | 6,706,428 | 0.18 | 28,300,854 | 237 |
47 | ![]() | 6,700,300 | 0.18 | 35,126,298 | 191 |
48 | ![]() | 6,692,684 | 0.18 | 10,430,738 | 642 |
49 | ![]() | 6,576,072 | 0.18 | 5,172,836 | 1,271 |
50 | ![]() | 6,182,464 | 0.17 | 55,339,003 | 112 |
51 | ![]() | 6,136,908 | 0.17 | 114,891,199 | 53 |
52 | ![]() | 5,914,408 | 0.16 | 9,686,463 | 611 |
53 | ![]() | 5,719,476 | 0.16 | 10,242,908 | 558 |
54 | ![]() | 5,583,136 | 0.15 | 10,642,081 | 525 |
55 | ![]() | 5,450,100 | 0.15 | 247,504,495 | 22 |
56 | ![]() | 4,779,612 | 0.13 | 1,273,588 | 3,753 |
57 | ![]() | 4,763,008 | 0.13 | 46,164,219 | 103 |
58 | ![]() | 4,290,248 | 0.12 | 6,795,803 | 631 |
59 | ![]() | 3,274,232 | 0.09 | 20,330,104 | 161 |
60 | ![]() | 3,242,752 | 0.09 | 33,845,617 | 96 |
61 | ![]() | 3,173,176 | 0.09 | 227,882,945 | 14 |
62 | ![]() | 2,737,684 | 0.07 | 5,518,055 | 496 |
63 | ![]() | 2,716,544 | 0.07 | 17,980,083 | 151 |
64 | ![]() | 2,673,328 | 0.07 | 2,118,396 | 1,262 |
65 | ![]() | 2,638,876 | 0.07 | 2,854,099 | 925 |
66 | ![]() | 2,445,736 | 0.07 | 3,388,081 | 722 |
67 | ![]() | 2,343,896 | 0.06 | 3,896,023 | 602 |
68 | ![]() | 2,331,940 | 0.06 | 5,105,525 | 457 |
69 | ![]() | 2,293,096 | 0.06 | 6,773,201 | 339 |
70 | ![]() | 2,191,828 | 0.06 | 33,787,914 | 65 |
71 | ![]() | 2,005,892 | 0.05 | 171,466,990 | 12 |
72 | ![]() | 1,906,664 | 0.05 | 4,838,782 | 394 |
73 | ![]() | 1,890,932 | 0.05 | 50,042,791 | 38 |
74 | ![]() | 1,843,756 | 0.05 | 1,882,396 | 979 |
75 | ![]() | 1,833,868 | 0.05 | 665,098 | 2,757 |
76 | ![]() | 1,789,820 | 0.05 | 9,115,680 | 196 |
77 | ![]() | 1,734,792 | 0.05 | 4,458,759 | 389 |
78 | ![]() | 1,712,196 | 0.05 | 31,165,654 | 55 |
79 | ![]() | 1,647,204 | 0.04 | 20,723,965 | 79 |
80 | ![]() | 1,615,252 | 0.04 | 11,331,265 | 143 |
81 | ![]() | 1,433,740 | 0.04 | 48,656,601 | 29 |
82 | ![]() | 1,310,620 | 0.04 | 1,367,196 | 959 |
83 | ![]() | 1,285,184 | 0.03 | 3,807,492 | 338 |
84 | ![]() | 1,276,856 | 0.03 | 23,594,623 | 54 |
85 | ![]() | 1,270,256 | 0.03 | 36,749,906 | 35 |
86 | ![]() | 1,267,832 | 0.03 | 1,344,976 | 943 |
87 | ![]() | 1,246,208 | 0.03 | 3,067,070 | 406 |
88 | ![]() | 1,169,452 | 0.03 | 12,244,159 | 96 |
89 | ![]() | 1,152,432 | 0.03 | 6,844,146 | 168 |
90 | ![]() | 1,076,812 | 0.03 | 66,617,606 | 16 |
91 | ![]() | 950,996 | 0.03 | 5,049,269 | 188 |
92 | ![]() | 894,364 | 0.02 | 387,558 | 2,308 |
93 | ![]() | 874,272 | 0.02 | 5,409,202 | 162 |
94 | ![]() | 843,604 | 0.02 | 2,979,082 | 283 |
95 | ![]() | 788,336 | 0.02 | 3,185,073 | 248 |
96 | ![]() | 767,228 | 0.02 | 10,318,207 | 74 |
![]() | 761,764 | 0.02 | 3,242,023 | 235 | |
97 | ![]() | 690,800 | 0.02 | 532,956 | 1,296 |
98 | ![]() | 685,508 | 0.02 | 1,831,802 | 374 |
99 | ![]() | 668,456 | 0.02 | 2,943,393 | 227 |
100 | ![]() | 663,728 | 0.02 | 6,309,624 | 105 |
101 | ![]() | 645,656 | 0.02 | 11,439,213 | 56 |
102 | ![]() | 642,748 | 0.02 | 18,124,838 | 35 |
103 | ![]() | 599,572 | 0.02 | 28,372,687 | 21 |
104 | ![]() | 578,460 | 0.02 | 31,195,932 | 19 |
105 | ![]() | 574,736 | 0.02 | 29,694,614 | 19 |
106 | ![]() | 567,096 | 0.02 | 5,773,493 | 98 |
107 | ![]() | 564,140 | 0.02 | 22,971,617 | 25 |
108 | ![]() | 554,816 | 0.02 | 21,104,482 | 26 |
109 | ![]() | 544,532 | 0.01 | 1,502,932 | 362 |
110 | ![]() | 534,528 | 0.01 | 10,644,851 | 50 |
111 | ![]() | 484,756 | 0.01 | 2,811,655 | 172 |
112 | ![]() | 465,008 | 0.01 | 2,963,095 | 157 |
113 | ![]() | 448,528 | 0.01 | 7,305,659 | 61 |
114 | ![]() | 445,476 | 0.01 | 1,569,666 | 284 |
115 | ![]() | 444,464 | 0.01 | 33,635,160 | 13 |
116 | ![]() | 443,400 | 0.01 | 45,074,049 | 10 |
![]() | 424,604 | 0.01 | 874,883 | 485 | |
117 | ![]() | 411,944 | 0.01 | 6,823,613 | 60 |
118 | ![]() | 406,764 | 0.01 | 17,423,880 | 23 |
119 | ![]() | 404,080 | 0.01 | 18,077,573 | 22 |
120 | ![]() | 393,632 | 0.01 | 2,484,789 | 158 |
121 | ![]() | 368,580 | 0.01 | 128,691,692 | 3 |
122 | ![]() | 353,728 | 0.01 | 9,304,337 | 38 |
![]() | 337,512 | 0.01 | 713,912 | 473 | |
123 | ![]() | 336,696 | 0.01 | 23,025,776 | 15 |
124 | ![]() | 286,300 | 0.01 | 35,652,307 | 8 |
125 | ![]() | 280,716 | 0.01 | 13,954,471 | 20 |
126 | ![]() | 272,808 | 0.01 | 2,697,845 | 101 |
127 | ![]() | 269,952 | 0.01 | 7,073,516 | 38 |
128 | ![]() | 256,940 | 0.01 | 11,019,931 | 23 |
129 | ![]() | 238,720 | 0.01 | 54,133,798 | 4 |
![]() | 237,024 | 0.01 | 38,471 | 6,161 | |
130 | ![]() | 233,352 | 0.01 | 39,390,799 | 6 |
131 | ![]() | 223,032 | 0.01 | 2,839,786 | 79 |
![]() | 219,276 | 0.01 | 166,506 | 1,317 | |
132 | ![]() | 216,168 | 0.01 | 458,949 | 471 |
133 | ![]() | 209,200 | 0.01 | 633,552 | 330 |
![]() | 200,004 | 0.01 | 185,427 | 1,079 | |
134 | ![]() | 180,312 | 0.00 | 93,316 | 1,932 |
135 | ![]() | 180,240 | 0.00 | 3,431,932 | 53 |
136 | ![]() | 176,892 | 0.00 | 41,454,761 | 4 |
137 | ![]() | 175,568 | 0.00 | 105,789,731 | 2 |
138 | ![]() | 168,584 | 0.00 | 282,336 | 597 |
![]() | 165,688 | 0.00 | 38,985 | 4,250 | |
139 | ![]() | 165,552 | 0.00 | 411,106 | 403 |
140 | ![]() | 161,852 | 0.00 | 2,480,244 | 65 |
![]() | 161,352 | 0.00 | 289,870 | 557 | |
141 | ![]() | 154,780 | 0.00 | 11,637,398 | 13 |
142 | ![]() | 147,576 | 0.00 | 14,111,034 | 10 |
![]() | 144,216 | 0.00 | 103,674 | 1,391 | |
143 | ![]() | 142,700 | 0.00 | 924,145 | 154 |
144 | ![]() | 141,488 | 0.00 | 6,182,885 | 23 |
145 | ![]() | 138,648 | 0.00 | 399,440 | 347 |
![]() | 134,568 | 0.00 | 346,002 | 389 | |
![]() | 131,064 | 0.00 | [b] | ||
![]() | 129,048 | 0.00 | 84,165 | 1,533 | |
![]() | 124,612 | 0.00 | 376,517 | 331 | |
146 | ![]() | 120,756 | 0.00 | 2,311,472 | 52 |
![]() | 118,460 | 0.00 | 85,701 | 1,382 | |
![]() | 111,820 | 0.00 | 107,939 | 1,036 | |
![]() | 111,684 | 0.00 | 64,698 | 1,726 | |
147 | ![]() | 105,996 | 0.00 | 39,598 | 2,677 |
148 | ![]() | 101,988 | 0.00 | 16,340,822 | 6 |
149 | ![]() | 93,764 | 0.00 | 525,994 | 178 |
150 | ![]() | 92,564 | 0.00 | 23,769,127 | 4 |
151 | ![]() | 87,580 | 0.00 | 7,664,993 | 11 |
152 | ![]() | 82,844 | 0.00 | 8,460,512 | 10 |
153 | ![]() | 82,712 | 0.00 | 10,389,799 | 8 |
154 | ![]() | 81,608 | 0.00 | 628,886 | 130 |
![]() | 75,444 | 0.00 | 281,118 | 268 | |
155 | ![]() | 72,436 | 0.00 | 10,389,635 | 7 |
156 | ![]() | 68,808 | 0.00 | 826,353 | 83 |
157 | ![]() | 63,660 | 0.00 | 38,956 | 1,634 |
158 | ![]() | 57,256 | 0.00 | 80,856 | 708 |
159 | ![]() | 54,176 | 0.00 | 1,230,506 | 44 |
160 | ![]() | 50,828 | 0.00 | 18,358,615 | 3 |
![]() | 48,276 | 0.00 | 73,038 | 661 | |
161 | ![]() | 46,284 | 0.00 | 5,022,441 | 9 |
162 | ![]() | 46,052 | 0.00 | 1,152,944 | 40 |
163 | ![]() | 45,008 | 0.00 | 26,159,867 | 2 |
![]() | 45,000 | 0.00 | 54,714 | 822 | |
164 | ![]() | 43,604 | 0.00 | 786,385 | 55 |
![]() | 40,608 | 0.00 | 64,017 | 634 | |
165 | ![]() | 39,092 | 0.00 | 5,493,031 | 7 |
166 | ![]() | 38,832 | 0.00 | 33,733 | 1,151 |
167 | ![]() | 38,052 | 0.00 | 522,331 | 73 |
168 | ![]() | 38,048 | 0.00 | 14,405,468 | 3 |
169 | ![]() | 36,812 | 0.00 | 13,689,450 | 3 |
![]() | 34,252 | 0.00 | 42,749 | 801 | |
![]() | 34,204 | 0.00 | 55,922 | 612 | |
170 | ![]() | 26,252 | 0.00 | 11,483,374 | 2 |
171 | ![]() | 25,776 | 0.00 | 19,319,064 | 1 |
![]() | 24,784 | 0.00 | 29,898 | 829 | |
172 | ![]() | 23,436 | 0.00 | 1,384,286 | 17 |
![]() | 22,504 | 0.00 | 303,402 | 74 | |
173 | ![]() | 21,980 | 0.00 | 7,364,438 | 3 |
174 | ![]() | 20,656 | 0.00 | 179,285 | 115 |
175 | ![]() | 19,904 | 0.00 | 216,663 | 92 |
176 | ![]() | 19,648 | 0.00 | 46,758 | 420 |
177 | ![]() | 17,880 | 0.00 | 1,847,549 | 10 |
178 | ![]() | 16,304 | 0.00 | 320,409 | 51 |
![]() | 15,336 | 0.00 | 45,143 | 340 | |
179 | ![]() | 14,536 | 0.00 | 66,510 | 219 |
180 | ![]() | 14,288 | 0.00 | 800,005 | 18 |
181 | ![]() | 11,476 | 0.00 | 104,597 | 110 |
182 | ![]() | 10,952 | 0.00 | 117,081 | 94 |
183 | ![]() | 10,736 | 0.00 | 496 | 21,645 |
![]() | 10,468 | 0.00 | 46,198 | 227 | |
184 | ![]() | 10,212 | 0.00 | 11,875 | 860 |
185 | ![]() | 10,196 | 0.00 | 101,323 | 101 |
![]() | 9,692 | 0.00 | 14,410 | 673 | |
186 | ![]() | 9,208 | 0.00 | 230,871 | 40 |
187 | ![]() | 8,696 | 0.00 | 14,222 | 611 |
188 | ![]() | 8,684 | 0.00 | 112,630 | 77 |
189 | ![]() | 8,188 | 0.00 | 9,816 | 834 |
190 | ![]() | 7,152 | 0.00 | 850,387 | 8 |
![]() | 7,124 | 0.00 | 3,477 | 2,049 | |
191 | ![]() | 6,128 | 0.00 | 17,727 | 346 |
192 | ![]() | 5,620 | 0.00 | 2,153,339 | 3 |
193 | ![]() | 5,356 | 0.00 | 5,152,421 | 1 |
![]() | 5,112 | 0.00 | 47,521 | 108 | |
![]() | 4,600 | 0.00 | 5,681 | 810 | |
194 | ![]() | 4,588 | 0.00 | 38,827 | 118 |
195 | ![]() | 4,092 | 0.00 | 3,470,390 | 1 |
![]() | 4,092 | 0.00 | 26,711 | 153 | |
196 | ![]() | 4,076 | 0.00 | 132,530 | 31 |
![]() | 3,572 | 0.00 | 11,370 | 314 | |
![]() | 3,556 | 0.00 | 27,515 | 129 | |
![]() | 3,064 | 0.00 | 4,000 | 766 | |
![]() | 3,052 | 0.00 | 2,397 | 1,273 | |
197 | ![]() | 2,040 | 0.00 | 1,817 | 1,123 |
![]() | 1,272 | 0.00 | 4,420 | 288 | |
198 | ![]() | 1,020 | 0.00 | 26,418,204 | 0 |
![]() | 1,020 | 0.00 | 316,015 | 3 | |
![]() | 760 | 0.00 | 1,828 | 416 | |
![]() | 756 | 0.00 | 11,085 | 68 | |
199 | ![]() | 0 | 1,700,031 | ||
199 | ![]() | 0 | 579,729 | ||
![]() | 0 | 5,289 | |||
![]() | 0 | 2,550 | |||
![]() | 0 | 1,500 | |||
![]() | 0 | 628 | |||
![]() | 0 | 140 | |||
![]() | 0 | 46 | |||
![]() | 0 | 30 | |||
![]() | 0 | 0 | |||
![]() | 0 | 0 | |||
![]() | 0 | 0 |
The American Registry for Internet Numbers (ARIN) is the regional Internet registry for the United States, Canada, and many Caribbean and North Atlantic islands. ARIN manages the distribution of Internet number resources, including IPv4 and IPv6 address space and AS numbers. ARIN opened for business on December 22, 1997 after incorporating on April 18, 1997. ARIN is a nonprofit corporation with headquarters in Chantilly, Virginia, United States.
An Internet Protocol address is a numerical label such as 192.0.2.1 that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface identification, and location addressing.
Internet Protocol version 4 (IPv4) is the first version of the Internet Protocol (IP) as a standalone specification. It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production on SATNET in 1982 and on the ARPANET in January 1983. It is still used to route most Internet traffic today, even with the ongoing deployment of Internet Protocol version 6 (IPv6), its successor.
Classless Inter-Domain Routing is a method for allocating IP addresses for IP routing. The Internet Engineering Task Force introduced CIDR in 1993 to replace the previous classful network addressing architecture on the Internet. Its goal was to slow the growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses.
A multicast address is a logical identifier for a group of hosts in a computer network that are available to process datagrams or frames intended to be multicast for a designated network service. Multicast addressing can be used in the link layer, such as Ethernet multicast, and at the internet layer for Internet Protocol Version 4 (IPv4) or Version 6 (IPv6) multicast.
APNIC is the regional Internet address registry (RIR) for the Asia–Pacific region. It is one of the world's five RIRs and is part of the Number Resource Organization (NRO).
The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol–related symbols and Internet numbers.
Bogon filtering is the practice of blocking packets known as bogons, which are ones sent to a computer network claiming to originate from invalid or bogus IP addresses, known as bogon addresses.
A regional Internet registry (RIR) is an organization that manages the allocation and registration of Internet number resources within a region of the world. Internet number resources include IP addresses and autonomous system (AS) numbers.
AFRINIC (African Network Information Centre) is the regional Internet registry (RIR) for Africa. Its headquarters are in Ebene, Mauritius.
A Martian packet is an IP packet seen on the public Internet that contains a source or destination address that is reserved for special use by the Internet Assigned Numbers Authority (IANA) as defined in RFC 1812, Appendix B Glossary. On the public Internet, such a packet either has a spoofed source address, and it cannot actually originate as claimed, or the packet cannot be delivered. The requirement to filter these packets is found in RFC 1812, Section 5.3.7.
In Internet networking, a private network is a computer network that uses a private address space of IP addresses. These addresses are commonly used for local area networks (LANs) in residential, office, and enterprise environments. Both the IPv4 and the IPv6 specifications define private IP address ranges.
RIPE NCC is the regional Internet registry (RIR) for Europe, the Middle East, and parts of Central Asia. Its headquarters are in Amsterdam, Netherlands, with a branch office in Dubai, UAE.
In the Internet addressing architecture, the Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have reserved various Internet Protocol (IP) addresses for special purposes.
IPv4 address exhaustion is the depletion of the pool of unallocated IPv4 addresses. Because the original Internet architecture had fewer than 4.3 billion addresses available, depletion has been anticipated since the late 1980s when the Internet started experiencing dramatic growth. This depletion is one of the reasons for the development and deployment of its successor protocol, IPv6. IPv4 and IPv6 coexist on the Internet.
A unique local address (ULA) is an Internet Protocol version 6 (IPv6) address in the address range fc00::/7. These addresses are non-globally reachable. For this reason, ULAs are somewhat analogous to IPv4 private network addressing, but with significant differences. Unique local addresses may be used freely, without centralized registration, inside a single site or organization or spanning a limited number of sites or organizations.
The Internet Protocol Version 4 address 0.0.0.0 can have multiple uses.
An Internet Protocol version 6 address is a numeric label that is used to identify and locate a network interface of a computer or a network node participating in a computer network using IPv6. IP addresses are included in the packet header to indicate the source and the destination of each packet. The IP address of the destination is used to make decisions about routing IP packets to other networks.
In order to ensure proper working of carrier-grade NAT (CGN), and, by doing so, alleviating the demand for the last remaining IPv4 addresses, a /10 size IPv4 address block was assigned by Internet Assigned Numbers Authority (IANA) to be used as shared address space. This block of addresses is specifically meant to be used by Internet service providers that implement carrier-grade NAT, to connect their customer-premises equipment (CPE) to their core routers.