| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ | 
| 1966 | 397122 | 232582 | 70193 | 22093 | 4434 | 1795 | 167 | 
| 1967 | 371759 | 280127 | 96182 | 25771 | 7040 | 1157 | 515 | 
| 1968 | 338744 | 259108 | 111636 | 33860 | 7806 | 1005 | 233 | 
| 1969 | 293314 | 235626 | 105135 | 36171 | 8761 | 2127 | 337 | 
| 1970 | 250948 | 201390 | 97246 | 37911 | 8607 | 2511 | 714 | 
| 1971 | 266199 | 172301 | 86855 | 34857 | 10434 | 2484 | 935 | 
| 1972 | 319336 | 186652 | 81471 | 32435 | 9564 | 4155 | 1355 | 
| 1973 | 403528 | 225934 | 87204 | 29703 | 9626 | 3621 | 2146 | 
| 1974 | 419157 | 295375 | 112533 | 32112 | 8874 | 3670 | 2231 | 
| 1975 | 322223 | 313640 | 150693 | 45026 | 10815 | 3300 | 2216 | 
| 1976 | 323515 | 237518 | 156530 | 62069 | 17199 | 4132 | 2130 | 
| 1977 | 449100 | 244019 | 127262 | 62007 | 21367 | 5619 | 2067 | 
| 1978 | 686252 | 346625 | 145801 | 56613 | 20873 | 6701 | 2403 | 
| 1979 | 582451 | 530195 | 210871 | 72403 | 22788 | 8772 | 3859 | 
| 1980 | 475918 | 434087 | 317426 | 103985 | 32048 | 9570 | 5251 | 
| 1981 | 624059 | 350109 | 252711 | 144351 | 39815 | 12697 | 5851 | 
| 1982 | 618468 | 474492 | 213844 | 110968 | 51380 | 13310 | 6274 | 
| 1983 | 446860 | 462314 | 285215 | 96375 | 39066 | 16518 | 6201 | 
| 1984 | 313013 | 324162 | 271848 | 128798 | 34787 | 13963 | 8209 | 
| 1985 | 262236 | 223239 | 174207 | 114462 | 43783 | 11039 | 7040 | 
| 1986 | 266732 | 183506 | 119014 | 69148 | 40175 | 14169 | 5860 | 
| 1987 | 293314 | 191186 | 99608 | 44135 | 20925 | 10000 | 5003 | 
| 1988 | 201592 | 209819 | 99808 | 37309 | 13773 | 5827 | 4169 | 
| 1989 | 121662 | 142914 | 100811 | 34787 | 12460 | 4442 | 3214 | 
| 1990 | 98815 | 86595 | 63704 | 29349 | 9447 | 3892 | 2410 | 
| 1991 | 91766 | 68734 | 38177 | 16933 | 6219 | 2526 | 1710 | 
| 1992 | 137173 | 64991 | 28339 | 9870 | 3061 | 1318 | 891 | 
| 1993 | 171271 | 101316 | 35313 | 10578 | 2665 | 794 | 569 | 
| 1994 | 137585 | 128027 | 61145 | 18429 | 4226 | 1287 | 661 | 
| 1995 | 120934 | 100007 | 73130 | 30394 | 7467 | 1867 | 874 | 
| 1996 | 107796 | 88433 | 54885 | 32273 | 10533 | 2755 | 993 | 
| 1997 | 94940 | 78747 | 44445 | 20221 | 8029 | 3942 | 1429 | 
| 1998 | 131268 | 70123 | 38369 | 15850 | 4349 | 2581 | 1736 | 
| 1999 | 138690 | 97636 | 37123 | 14102 | 3522 | 1481 | 1484 | 
| 2000 | 144640 | 101620 | 49961 | 13581 | 3400 | 1268 | 1081 | 
| 2001 | 120572 | 102950 | 48776 | 15337 | 3239 | 1222 | 841 | 
| 2002 | 112758 | 85734 | 46911 | 13281 | 3416 | 1139 | 733 | 
| 2003 | 93526 | 80017 | 40538 | 13382 | 2945 | 1118 | 618 | 
| 2004 | 102744 | 67440 | 37272 | 10934 | 3255 | 1019 | 600 | 
| 2005 | 125492 | 75811 | 34235 | 10763 | 2369 | 785 | 393 | 
| 2006 | 108120 | 93901 | 42959 | 12313 | 2710 | 739 | 368 | 
| 2007 | 131531 | 79858 | 51896 | 18590 | 3614 | 873 | 364 | 
| 2008 | 139804 | 101824 | 50716 | 20576 | 6076 | 1219 | 416 | 
| 2009 | 129314 | 108337 | 67711 | 24835 | 6419 | 1920 | 513 | 
| 2010 | 121905 | 101824 | 76191 | 34475 | 7030 | 1387 | 543 | 
| 2011 | 135402 | 96182 | 72911 | 37835 | 10269 | 2022 | 557 | 
| 2012 | 135537 | 107689 | 68665 | 37873 | 9871 | 1296 | 328 | 
| 2013 | 170416 | 105768 | 73865 | 33827 | 10728 | 1529 | 248 | 
| 2014 | 190804 | 135808 | 75735 | 38561 | 8756 | 2761 | 457 |