| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ | 
| 1963 | 398714 | 168890 | 19964 | 10187 | 8065 | 4867 | 
| 1964 | 650828 | 120331 | 51637 | 11447 | 5178 | 6656 | 
| 1965 | 874144 | 206076 | 40417 | 22857 | 6159 | 5230 | 
| 1966 | 1062356 | 252458 | 67711 | 16308 | 9298 | 5853 | 
| 1967 | 890911 | 308661 | 72911 | 28481 | 7982 | 7833 | 
| 1968 | 448651 | 263814 | 90219 | 28739 | 14264 | 6750 | 
| 1969 | 391993 | 127389 | 72114 | 33928 | 11295 | 9625 | 
| 1970 | 1322454 | 118658 | 38832 | 32112 | 15259 | 8022 | 
| 1971 | 1737573 | 383847 | 33658 | 14946 | 16017 | 10212 | 
| 1972 | 429338 | 479261 | 91126 | 12160 | 5974 | 12490 | 
| 1973 | 635394 | 108880 | 106085 | 30001 | 4958 | 6867 | 
| 1974 | 631593 | 163734 | 23647 | 36388 | 10922 | 5390 | 
| 1975 | 1087074 | 157787 | 36864 | 9690 | 16385 | 6921 | 
| 1976 | 753135 | 272393 | 34098 | 13702 | 3799 | 9577 | 
| 1977 | 1833982 | 165877 | 51124 | 10795 | 5106 | 5952 | 
| 1978 | 1120180 | 429768 | 30915 | 18839 | 5659 | 4472 | 
| 1979 | 1400024 | 258074 | 80983 | 8903 | 7324 | 3389 | 
| 1980 | 2260282 | 301040 | 59338 | 24563 | 3973 | 4534 | 
| 1981 | 875894 | 482145 | 59278 | 17624 | 8761 | 3503 | 
| 1982 | 1441219 | 182408 | 93901 | 17029 | 6591 | 5482 | 
| 1983 | 799706 | 310209 | 33591 | 21269 | 5403 | 4371 | 
| 1984 | 1476227 | 173338 | 52523 | 7974 | 6737 | 3732 | 
| 1985 | 358255 | 328076 | 33290 | 14716 | 2759 | 4082 | 
| 1986 | 1618483 | 84373 | 58513 | 10177 | 5616 | 2908 | 
| 1987 | 617232 | 383080 | 16692 | 15438 | 2995 | 3280 | 
| 1988 | 425917 | 150242 | 71682 | 5281 | 4928 | 2293 | 
| 1989 | 746387 | 105662 | 30761 | 17375 | 1831 | 2886 | 
| 1990 | 296559 | 180593 | 20535 | 7881 | 5100 | 1629 | 
| 1991 | 341465 | 74907 | 30946 | 6015 | 2688 | 2916 | 
| 1992 | 798907 | 90310 | 15181 | 8835 | 2032 | 2008 | 
| 1993 | 398316 | 201793 | 18312 | 5035 | 2844 | 1553 | 
| 1994 | 966078 | 107689 | 37198 | 5524 | 1727 | 1688 | 
| 1995 | 554599 | 251954 | 24101 | 10385 | 1803 | 1292 | 
| 1996 | 355400 | 142486 | 41399 | 5703 | 3376 | 1404 | 
| 1997 | 1110144 | 101013 | 27201 | 9669 | 1876 | 1674 | 
| 1998 | 113437 | 308045 | 22226 | 7123 | 3081 | 1236 | 
| 1999 | 233281 | 33223 | 56275 | 5539 | 2074 | 1565 | 
| 2000 | 430628 | 67171 | 8707 | 9895 | 1500 | 1057 | 
| 2001 | 156217 | 128412 | 14536 | 2198 | 2279 | 732 | 
| 2002 | 236570 | 48923 | 26318 | 3897 | 599 | 944 | 
| 2003 | 115844 | 67914 | 11172 | 7249 | 1089 | 527 | 
| 2004 | 198789 | 37571 | 14613 | 3066 | 2014 | 573 | 
| 2005 | 154972 | 54940 | 8465 | 3403 | 1005 | 1048 | 
| 2006 | 361855 | 48098 | 13129 | 2217 | 1106 | 924 | 
| 2007 | 170246 | 104193 | 10554 | 4196 | 981 | 798 | 
| 2008 | 192144 | 48146 | 24909 | 3208 | 1638 | 984 | 
| 2009 | 184610 | 54502 | 11819 | 7676 | 1408 | 1130 | 
| 2010 | 277063 | 54830 | 13529 | 3949 | 3222 | 1062 | 
| 2011 | 134188 | 78590 | 13749 | 4256 | 1711 | 2116 | 
| 2012 | 181135 | 40175 | 20476 | 5909 | 1906 | 1838 | 
| 2013 | 228662 | 50919 | 11441 | 8639 | 2876 | 1778 | 
| 2014 | 321258 | 64408 | 15802 | 5008 | 4152 | 2227 | 
| 2015 | 157472 | 92596 | 20523 | 6403 | 2393 | 3808 | 
| 2016 | 111748 | 41773 | 26796 | 10160 | 3275 | 2820 | 
| 2017 | 394352 | 28339 | 12988 | 11305 | 5421 | 3147 | 
| 2018 | 98322 | 99808 | 8429 | 5395 | 5018 | 4877 |