| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ |
| 1966 | 406362 | 232350 | 69217 | 22449 | 4432 | 1770 | 171 |
| 1967 | 372503 | 287506 | 96955 | 25489 | 7386 | 1220 | 540 |
| 1968 | 341806 | 259108 | 114234 | 34269 | 7793 | 966 | 221 |
| 1969 | 292436 | 237518 | 104297 | 36316 | 8761 | 2184 | 334 |
| 1970 | 246225 | 199786 | 97343 | 37835 | 8493 | 2522 | 735 |
| 1971 | 264342 | 168215 | 85734 | 34857 | 10473 | 2408 | 929 |
| 1972 | 316475 | 184979 | 81227 | 32403 | 9496 | 4286 | 1358 |
| 1973 | 411268 | 222793 | 86077 | 29644 | 9661 | 3580 | 2215 |
| 1974 | 435391 | 301040 | 111748 | 31508 | 8760 | 3688 | 2260 |
| 1975 | 315212 | 327093 | 153737 | 44981 | 10702 | 3250 | 2236 |
| 1976 | 312700 | 232350 | 160011 | 63704 | 17794 | 4140 | 2155 |
| 1977 | 449999 | 236807 | 123871 | 62069 | 21738 | 5712 | 2053 |
| 1978 | 717121 | 349410 | 143487 | 55271 | 20313 | 6611 | 2352 |
| 1979 | 585370 | 554599 | 214486 | 72475 | 22584 | 8760 | 3913 |
| 1980 | 460929 | 435391 | 331373 | 107152 | 33124 | 9605 | 5306 |
| 1981 | 636666 | 339083 | 251702 | 148598 | 40538 | 13174 | 5915 |
| 1982 | 634124 | 485532 | 209819 | 109535 | 51792 | 13320 | 6379 |
| 1983 | 450900 | 474018 | 292728 | 95320 | 38407 | 16454 | 6124 |
| 1984 | 309279 | 326766 | 280408 | 132720 | 34752 | 13991 | 8348 |
| 1985 | 254486 | 219916 | 173338 | 117008 | 44267 | 10936 | 7030 |
| 1986 | 265933 | 177017 | 117008 | 69217 | 41773 | 14562 | 5925 |
| 1987 | 307122 | 190804 | 97149 | 43217 | 20595 | 9992 | 4930 |
| 1988 | 207939 | 219038 | 100208 | 36717 | 13544 | 5730 | 4137 |
| 1989 | 123007 | 147267 | 104820 | 35242 | 12701 | 4448 | 3227 |
| 1990 | 100912 | 87904 | 65382 | 29971 | 9589 | 3994 | 2444 |
| 1991 | 88876 | 70123 | 39262 | 17304 | 6277 | 2570 | 1761 |
| 1992 | 135537 | 62818 | 27612 | 9708 | 3051 | 1303 | 888 |
| 1993 | 174033 | 100108 | 34579 | 10275 | 2647 | 778 | 553 |
| 1994 | 135537 | 130353 | 61698 | 18851 | 4344 | 1345 | 683 |
| 1995 | 119850 | 98420 | 74682 | 31008 | 7752 | 1945 | 928 |
| 1996 | 108120 | 87641 | 54557 | 33124 | 10764 | 2807 | 1013 |
| 1997 | 92411 | 79142 | 43565 | 20024 | 8261 | 4077 | 1485 |
| 1998 | 134592 | 68528 | 37835 | 15540 | 4548 | 2655 | 1794 |
| 1999 | 143057 | 100509 | 36864 | 14133 | 3666 | 1602 | 1576 |
| 2000 | 148153 | 105345 | 52104 | 13852 | 3587 | 1359 | 1197 |
| 2001 | 128284 | 104925 | 50919 | 16051 | 3481 | 1313 | 927 |
| 2002 | 126121 | 91217 | 47667 | 13996 | 3732 | 1264 | 820 |
| 2003 | 100408 | 89322 | 43739 | 14025 | 3153 | 1221 | 691 |
| 2004 | 109207 | 72693 | 41982 | 11669 | 3601 | 1101 | 668 |
| 2005 | 163244 | 80338 | 37272 | 12274 | 2525 | 799 | 396 |
| 2006 | 155127 | 123995 | 46074 | 13854 | 3513 | 796 | 381 |
| 2007 | 174381 | 118184 | 71826 | 21169 | 4840 | 1296 | 438 |
| 2008 | 194075 | 135944 | 77886 | 28710 | 7667 | 1760 | 638 |
| 2009 | 176134 | 152818 | 92319 | 37384 | 12211 | 3506 | 1082 |
| 2010 | 188339 | 137585 | 105768 | 46817 | 16992 | 5671 | 2169 |
| 2011 | 223910 | 148598 | 95607 | 51792 | 21438 | 8313 | 3846 |
| 2012 | 253977 | 178082 | 101519 | 47382 | 24736 | 10231 | 5815 |
| 2013 | 312388 | 202400 | 119731 | 47858 | 21363 | 13533 | 8781 |