| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ |
| 1966 | 402319 | 232582 | 69913 | 22181 | 4435 | 1788 | 168 |
| 1967 | 372503 | 283793 | 96375 | 25694 | 7120 | 1173 | 522 |
| 1968 | 340442 | 259627 | 112758 | 33962 | 7803 | 996 | 229 |
| 1969 | 291560 | 236807 | 105030 | 36316 | 8760 | 2141 | 336 |
| 1970 | 246225 | 200586 | 97538 | 37911 | 8583 | 2512 | 720 |
| 1971 | 263550 | 169397 | 86422 | 34926 | 10438 | 2464 | 933 |
| 1972 | 316792 | 185165 | 80741 | 32403 | 9558 | 4187 | 1355 |
| 1973 | 409626 | 224358 | 86509 | 29525 | 9635 | 3609 | 2167 |
| 1974 | 429338 | 299539 | 111972 | 31857 | 8821 | 3672 | 2242 |
| 1975 | 316475 | 321258 | 152512 | 44936 | 10774 | 3277 | 2223 |
| 1976 | 316475 | 233048 | 159213 | 62818 | 17327 | 4127 | 2135 |
| 1977 | 450900 | 238709 | 124991 | 62505 | 21539 | 5634 | 2063 |
| 1978 | 711407 | 348015 | 143487 | 55770 | 20831 | 6696 | 2384 |
| 1979 | 583617 | 547983 | 212352 | 71754 | 22539 | 8803 | 3878 |
| 1980 | 463703 | 434087 | 327420 | 105030 | 32112 | 9522 | 5283 |
| 1981 | 636666 | 341465 | 252458 | 147709 | 40095 | 12753 | 5857 |
| 1982 | 632225 | 483110 | 209400 | 110525 | 52052 | 13317 | 6277 |
| 1983 | 448651 | 472125 | 290396 | 94940 | 38832 | 16649 | 6155 |
| 1984 | 308970 | 325462 | 277618 | 131006 | 34406 | 13934 | 8289 |
| 1985 | 256530 | 220577 | 174207 | 116308 | 44223 | 10921 | 7048 |
| 1986 | 266732 | 179692 | 117712 | 69217 | 40864 | 14347 | 5847 |
| 1987 | 302852 | 191377 | 97929 | 43695 | 20848 | 10043 | 4988 |
| 1988 | 204638 | 216642 | 100208 | 36901 | 13690 | 5806 | 4174 |
| 1989 | 121419 | 145219 | 103777 | 34996 | 12501 | 4448 | 3230 |
| 1990 | 99310 | 86682 | 64731 | 29882 | 9562 | 3935 | 2440 |
| 1991 | 90400 | 69425 | 38600 | 17197 | 6344 | 2590 | 1758 |
| 1992 | 139525 | 64216 | 28681 | 9999 | 3118 | 1340 | 901 |
| 1993 | 176663 | 103156 | 35277 | 10840 | 2759 | 818 | 583 |
| 1994 | 137585 | 132058 | 62944 | 18802 | 4431 | 1360 | 695 |
| 1995 | 122762 | 100007 | 75735 | 31414 | 7696 | 1947 | 920 |
| 1996 | 109535 | 90039 | 55381 | 33456 | 11080 | 2848 | 1027 |
| 1997 | 96086 | 80258 | 45844 | 20794 | 8628 | 4276 | 1525 |
| 1998 | 142771 | 71182 | 39616 | 16639 | 4572 | 2866 | 1940 |
| 1999 | 144784 | 107045 | 38407 | 14716 | 3746 | 1521 | 1584 |
| 2000 | 161943 | 106298 | 56500 | 14541 | 3496 | 1387 | 1150 |
| 2001 | 149044 | 116192 | 53637 | 18014 | 3372 | 1237 | 887 |
| 2002 | 145947 | 107152 | 56557 | 16084 | 3997 | 1173 | 743 |
| 2003 | 124119 | 103156 | 54557 | 18393 | 3696 | 1278 | 600 |
| 2004 | 122149 | 89054 | 52000 | 17693 | 5365 | 1281 | 613 |