| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ |
| 1963 | 483110 | 187025 | 20123 | 10320 | 8238 | 5253 |
| 1964 | 787800 | 132588 | 51844 | 11555 | 5269 | 7117 |
| 1965 | 1053891 | 226613 | 40457 | 23040 | 6239 | 5611 |
| 1966 | 1278247 | 277340 | 67846 | 16470 | 9458 | 6237 |
| 1967 | 1073033 | 338405 | 73057 | 28739 | 8076 | 8299 |
| 1968 | 537132 | 289816 | 90310 | 28941 | 14439 | 7181 |
| 1969 | 469771 | 139525 | 72403 | 34201 | 11469 | 10178 |
| 1970 | 1572221 | 129573 | 38793 | 32306 | 15432 | 8519 |
| 1971 | 2051332 | 418319 | 33591 | 14968 | 16075 | 10715 |
| 1972 | 504842 | 521779 | 90853 | 12164 | 5985 | 12945 |
| 1973 | 741922 | 118421 | 105979 | 30001 | 4966 | 7198 |
| 1974 | 725778 | 177371 | 23671 | 36498 | 11007 | 5643 |
| 1975 | 1246687 | 168384 | 36754 | 9666 | 16437 | 7211 |
| 1976 | 862853 | 288082 | 33860 | 13636 | 3795 | 9904 |
| 1977 | 2118036 | 173859 | 50919 | 10799 | 5108 | 6186 |
| 1978 | 1301464 | 447754 | 30730 | 18783 | 5637 | 4644 |
| 1979 | 1642943 | 266999 | 80338 | 8913 | 7336 | 3533 |
| 1980 | 2660434 | 311763 | 58689 | 24563 | 3962 | 4683 |
| 1981 | 1043405 | 497823 | 58689 | 17610 | 8774 | 3624 |
| 1982 | 1718565 | 188905 | 92503 | 17012 | 6569 | 5613 |
| 1983 | 943168 | 320296 | 33057 | 21205 | 5396 | 4492 |
| 1984 | 1742794 | 177726 | 51637 | 7988 | 6714 | 3842 |
| 1985 | 416233 | 336718 | 32860 | 14734 | 2756 | 4202 |
| 1986 | 1897409 | 85648 | 57584 | 10225 | 5598 | 2999 |
| 1987 | 712831 | 393171 | 16358 | 15427 | 2996 | 3371 |
| 1988 | 484077 | 152360 | 70263 | 5258 | 4926 | 2370 |
| 1989 | 850858 | 106831 | 30273 | 17417 | 1837 | 2963 |
| 1990 | 328404 | 184425 | 20149 | 7913 | 5133 | 1693 |
| 1991 | 377377 | 75282 | 30516 | 6057 | 2707 | 3005 |
| 1992 | 884697 | 91400 | 14879 | 8900 | 2047 | 2090 |
| 1993 | 431922 | 205253 | 18128 | 5093 | 2894 | 1625 |
| 1994 | 1058115 | 107689 | 36680 | 5620 | 1764 | 1761 |
| 1995 | 605010 | 255506 | 23718 | 10515 | 1838 | 1351 |
| 1996 | 381933 | 143057 | 40619 | 5784 | 3412 | 1453 |
| 1997 | 1217122 | 100408 | 26370 | 9778 | 1892 | 1728 |
| 1998 | 120813 | 312700 | 21694 | 7276 | 3153 | 1292 |
| 1999 | 249447 | 33157 | 55715 | 5761 | 2157 | 1645 |
| 2000 | 456800 | 67104 | 8467 | 10334 | 1562 | 1116 |
| 2001 | 163898 | 127899 | 14114 | 2271 | 2363 | 773 |
| 2002 | 249197 | 48776 | 25566 | 4058 | 624 | 996 |
| 2003 | 118895 | 67778 | 10839 | 7553 | 1146 | 559 |
| 2004 | 201995 | 36975 | 14132 | 3182 | 2101 | 604 |
| 2005 | 152818 | 53263 | 8041 | 3526 | 1031 | 1088 |
| 2006 | 358613 | 45798 | 12253 | 2255 | 1121 | 945 |
| 2007 | 167711 | 99907 | 9909 | 4254 | 997 | 824 |
| 2008 | 193881 | 46074 | 23389 | 3297 | 1681 | 1014 |
| 2009 | 188151 | 53104 | 11173 | 7828 | 1446 | 1174 |
| 2010 | 291851 | 53852 | 12944 | 4082 | 3328 | 1116 |
| 2011 | 143057 | 78747 | 13241 | 4470 | 1809 | 2243 |
| 2012 | 199786 | 40417 | 19996 | 6217 | 2034 | 1973 |
| 2013 | 260407 | 51586 | 11133 | 9144 | 3085 | 1921 |
| 2014 | 365127 | 66105 | 15383 | 5330 | 4481 | 2421 |
| 2015 | 175431 | 97343 | 20325 | 6960 | 2628 | 4180 |
| 2016 | 122516 | 43695 | 27282 | 11250 | 3745 | 3225 |
| 2017 | 619706 | 29614 | 13095 | 13186 | 6253 | 4261 |