| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ |
| 1966 | 386544 | 242559 | 68050 | 20986 | 4590 | 1674 | 172 |
| 1967 | 346625 | 297450 | 97052 | 24343 | 6557 | 1426 | 659 |
| 1968 | 339083 | 253723 | 121055 | 33490 | 6849 | 1082 | 182 |
| 1969 | 379648 | 249696 | 98223 | 37049 | 8715 | 1919 | 328 |
| 1970 | 269682 | 218163 | 101013 | 35031 | 8347 | 2246 | 726 |
| 1971 | 288947 | 164062 | 86250 | 36243 | 9062 | 1937 | 765 |
| 1972 | 397122 | 205253 | 85991 | 33057 | 10230 | 3534 | 1087 |
| 1973 | 417066 | 227977 | 91400 | 31952 | 10108 | 2527 | 2275 |
| 1974 | 416649 | 316159 | 111525 | 32273 | 9092 | 3131 | 2273 |
| 1975 | 356825 | 407991 | 165711 | 43434 | 10802 | 2834 | 2183 |
| 1976 | 170928 | 228662 | 193494 | 72114 | 20933 | 3917 | 2380 |
| 1977 | 164062 | 162592 | 114921 | 69773 | 24077 | 6311 | 2568 |
| 1978 | 797311 | 256786 | 117595 | 50869 | 20098 | 6587 | 2314 |
| 1979 | 828192 | 612926 | 197008 | 62755 | 20595 | 8297 | 4144 |
| 1980 | 353274 | 475442 | 371759 | 116658 | 34098 | 9835 | 4707 |
| 1981 | 426770 | 238948 | 245733 | 158261 | 45890 | 14177 | 6301 |
| 1982 | 587717 | 419157 | 174207 | 103881 | 50061 | 14223 | 7802 |
| 1983 | 566368 | 439767 | 277340 | 87204 | 37235 | 17115 | 5433 |
| 1984 | 319017 | 356468 | 282660 | 138275 | 35207 | 13022 | 9189 |
| 1985 | 387705 | 221018 | 167376 | 112308 | 43174 | 10637 | 6831 |
| 1986 | 189094 | 164226 | 114234 | 69494 | 46444 | 15193 | 6488 |
| 1987 | 502826 | 169397 | 85819 | 40135 | 19289 | 10441 | 5406 |
| 1988 | 295966 | 283793 | 97734 | 32209 | 11957 | 5532 | 3991 |
| 1989 | 80338 | 178082 | 123748 | 37123 | 12735 | 4086 | 2930 |
| 1990 | 178082 | 77343 | 70123 | 32338 | 10274 | 3527 | 2446 |
| 1991 | 65121 | 84542 | 41606 | 18902 | 6274 | 2443 | 1955 |
| 1992 | 110525 | 44091 | 25261 | 9188 | 2887 | 1397 | 830 |
| 1993 | 225483 | 95416 | 26291 | 8773 | 2258 | 666 | 442 |
| 1994 | 184979 | 161781 | 63513 | 19247 | 4667 | 1181 | 688 |
| 1995 | 154045 | 105451 | 79858 | 32533 | 8131 | 2087 | 1188 |
| 1996 | 160171 | 103881 | 58221 | 35703 | 11604 | 3032 | 890 |
| 1997 | 50413 | 93807 | 45252 | 19801 | 8494 | 3744 | 1793 |
| 1998 | 144784 | 53530 | 37684 | 16012 | 4638 | 2462 | 1735 |
| 1999 | 121905 | 106404 | 35277 | 14196 | 3772 | 1367 | 1476 |
| 2000 | 257816 | 106298 | 56162 | 14698 | 3492 | 1102 | 1104 |
| 2001 | 162592 | 122027 | 54285 | 16907 | 3460 | 1185 | 705 |
| 2002 | 145510 | 104193 | 51896 | 14666 | 3848 | 1121 | 790 |
| 2003 | 129573 | 91491 | 49119 | 15113 | 3259 | 1045 | 634 |
| 2004 | 98322 | 76420 | 44356 | 13791 | 4401 | 1237 | 686 |
| 2005 | 192336 | 76420 | 39935 | 12758 | 2783 | 853 | 460 |
| 2006 | 184425 | 148449 | 45661 | 15289 | 3827 | 875 | 455 |
| 2007 | 202400 | 138829 | 91035 | 25160 | 5869 | 1442 | 545 |
| 2008 | 317109 | 227977 | 121176 | 44179 | 11077 | 2661 | 1105 |
| 2009 | 305590 | 272665 | 139386 | 62069 | 20597 | 5540 | 1492 |
| 2010 | 263024 | 252458 | 200988 | 87992 | 31666 | 8817 | 3360 |
| 2011 | 366590 | 249197 | 146972 | 69355 | 28681 | 11556 | 4996 |
| 2012 | 275130 | 313326 | 171957 | 75132 | 23981 | 7245 | 4272 |
| 2013 | 294490 | 241108 | 156373 | 63895 | 22925 | 6562 | 2235 |
| 2014 | 399912 | 234451 | 98027 | 32893 | 7649 | 4565 | 1751 |