| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ | 
| 1966 | 407176 | 232350 | 69148 | 22494 | 4431 | 1767 | 171 | 
| 1967 | 372503 | 288370 | 97052 | 25438 | 7441 | 1230 | 543 | 
| 1968 | 342148 | 259108 | 114462 | 34338 | 7789 | 960 | 220 | 
| 1969 | 292728 | 237756 | 104193 | 36316 | 8761 | 2193 | 334 | 
| 1970 | 246225 | 199586 | 97343 | 37835 | 8477 | 2525 | 738 | 
| 1971 | 264342 | 168047 | 85562 | 34857 | 10483 | 2398 | 928 | 
| 1972 | 316159 | 184979 | 81389 | 32403 | 9483 | 4306 | 1359 | 
| 1973 | 411679 | 222571 | 85991 | 29673 | 9668 | 3574 | 2224 | 
| 1974 | 436699 | 301342 | 111636 | 31445 | 8748 | 3691 | 2263 | 
| 1975 | 314897 | 328076 | 154045 | 44981 | 10686 | 3245 | 2239 | 
| 1976 | 312075 | 232118 | 160171 | 63895 | 17892 | 4143 | 2159 | 
| 1977 | 449999 | 236570 | 123624 | 61945 | 21777 | 5730 | 2051 | 
| 1978 | 718557 | 349759 | 143487 | 55160 | 20209 | 6595 | 2347 | 
| 1979 | 585370 | 556265 | 215130 | 72620 | 22584 | 8751 | 3920 | 
| 1980 | 460469 | 435391 | 332369 | 107581 | 33323 | 9618 | 5310 | 
| 1981 | 637303 | 338744 | 251450 | 148747 | 40619 | 13260 | 5924 | 
| 1982 | 634759 | 486018 | 210029 | 109316 | 51741 | 13320 | 6398 | 
| 1983 | 451351 | 474492 | 293021 | 95416 | 38330 | 16414 | 6119 | 
| 1984 | 309279 | 327093 | 280969 | 133119 | 34822 | 14004 | 8360 | 
| 1985 | 254231 | 219916 | 173165 | 117125 | 44267 | 10940 | 7025 | 
| 1986 | 265933 | 176487 | 116891 | 69286 | 41982 | 14605 | 5943 | 
| 1987 | 307737 | 190613 | 96955 | 43174 | 20544 | 9984 | 4918 | 
| 1988 | 208564 | 219696 | 100308 | 36680 | 13518 | 5718 | 4132 | 
| 1989 | 123377 | 147561 | 105030 | 35277 | 12748 | 4450 | 3228 | 
| 1990 | 101316 | 88168 | 65513 | 30001 | 9607 | 4011 | 2448 | 
| 1991 | 88787 | 70333 | 39458 | 17368 | 6283 | 2576 | 1768 | 
| 1992 | 135402 | 62693 | 27447 | 9679 | 3049 | 1302 | 888 | 
| 1993 | 174207 | 100007 | 34579 | 10217 | 2642 | 776 | 552 | 
| 1994 | 135537 | 130614 | 61821 | 18955 | 4357 | 1352 | 686 | 
| 1995 | 119970 | 98420 | 74757 | 31101 | 7806 | 1954 | 935 | 
| 1996 | 108120 | 87641 | 54612 | 33223 | 10798 | 2815 | 1014 | 
| 1997 | 92226 | 79142 | 43521 | 20002 | 8259 | 4096 | 1492 | 
| 1998 | 134726 | 68460 | 37722 | 15499 | 4545 | 2650 | 1799 | 
| 1999 | 143487 | 100710 | 36864 | 14108 | 3666 | 1603 | 1579 | 
| 2000 | 148598 | 105662 | 52313 | 13876 | 3588 | 1361 | 1201 | 
| 2001 | 130353 | 105135 | 51124 | 16112 | 3478 | 1314 | 929 | 
| 2002 | 127134 | 92596 | 47810 | 14062 | 3757 | 1265 | 822 | 
| 2003 | 101013 | 89859 | 44578 | 14187 | 3143 | 1227 | 691 | 
| 2004 | 108337 | 72984 | 42193 | 11827 | 3635 | 1101 | 671 | 
| 2005 | 160332 | 79459 | 37309 | 12285 | 2508 | 792 | 390 | 
| 2006 | 170758 | 121176 | 45161 | 13683 | 3451 | 779 | 372 | 
| 2007 | 193107 | 131268 | 69148 | 20323 | 4662 | 1242 | 418 | 
| 2008 | 211716 | 151752 | 89232 | 33894 | 9109 | 2117 | 765 | 
| 2009 | 192721 | 167544 | 105556 | 40701 | 13654 | 3962 | 1236 | 
| 2010 | 202197 | 151297 | 118302 | 50413 | 17529 | 5935 | 2298 | 
| 2011 | 237994 | 160171 | 106938 | 53960 | 21433 | 7864 | 3689 | 
| 2012 | 269413 | 189852 | 110968 | 49365 | 23506 | 9057 | 4900 | 
| 2013 | 329062 | 215346 | 129314 | 48339 | 20252 | 11273 | 6692 |