| Table 3. Estimated stock numbers at age. | ||||||
| Year Age | 1 | 2 | 3 | 4 | 5 | 6 | 
| 1968 | 2780 | 3710 | 1860 | 922 | 384 | 62 | 
| 1969 | 4677 | 2359 | 1652 | 623 | 340 | 188 | 
| 1970 | 7204 | 3285 | 791 | 446 | 266 | 151 | 
| 1971 | 12615 | 4610 | 1647 | 313 | 162 | 131 | 
| 1972 | 4849 | 7944 | 1911 | 635 | 138 | 135 | 
| 1973 | 9967 | 2722 | 3398 | 820 | 314 | 142 | 
| 1974 | 2999 | 7126 | 1151 | 1113 | 296 | 163 | 
| 1975 | 7603 | 1622 | 2821 | 468 | 451 | 202 | 
| 1976 | 4004 | 5633 | 702 | 990 | 135 | 213 | 
| 1977 | 4143 | 1565 | 2228 | 276 | 380 | 131 | 
| 1978 | 4430 | 2716 | 660 | 730 | 94 | 166 | 
| 1979 | 9212 | 3012 | 1262 | 264 | 302 | 125 | 
| 1980 | 12059 | 6245 | 1362 | 497 | 101 | 131 | 
| 1981 | 6572 | 7570 | 2727 | 491 | 202 | 94 | 
| 1982 | 2353 | 4302 | 2813 | 979 | 181 | 128 | 
| 1983 | 4175 | 1840 | 1469 | 928 | 310 | 95 | 
| 1984 | 7030 | 2685 | 805 | 473 | 312 | 143 | 
| 1985 | 6185 | 4112 | 1171 | 298 | 164 | 154 | 
| 1986 | 5269 | 4158 | 1351 | 381 | 112 | 117 | 
| 1987 | 15144 | 3364 | 1470 | 427 | 130 | 76 | 
| 1988 | 8820 | 8691 | 1175 | 438 | 125 | 64 | 
| 1989 | 2921 | 3904 | 2738 | 357 | 132 | 58 | 
| 1990 | 3568 | 1907 | 933 | 625 | 103 | 49 | 
| 1991 | 5882 | 2485 | 653 | 215 | 167 | 38 | 
| 1992 | 5351 | 2281 | 872 | 159 | 55 | 62 | 
| 1993 | 1238 | 3943 | 469 | 148 | 24 | 21 | 
| 1994 | 3096 | 835 | 1084 | 82 | 26 | 12 | 
| 1995 | 2570 | 2134 | 237 | 215 | 13 | 9 | 
| 1996 | 1829 | 1606 | 830 | 56 | 59 | 8 | 
| 1997 | 2787 | 1557 | 560 | 209 | 18 | 21 | 
| 1998 | 1080 | 2808 | 430 | 98 | 33 | 9 | 
| 1999 | 324 | 969 | 951 | 77 | 21 | 8 | 
| 2000 | 1972 | 236 | 141 | 77 | 7 | 2 | 
| 2001 | 1721 | 1467 | 64 | 18 | 14 | 3 | 
| 2002 | 1237 | 883 | 471 | 11 | 3 | 3 | 
| 2003 | 462 | 919 | 168 | 53 | 2 | 1 | 
| 2004 | 657 | 267 | 287 | 36 | 10 | 2 | 
| 2005 | 399 | 502 | 96 | 53 | 8 | 2 | 
| 2006 | 262 | 252 | 179 | 17 | 9 | 3 | 
| 2007 | 426 | 304 | 78 | 20 | 1 | 1 | 
| 2008 | 143 | 285 | 106 | 14 | 4 | 0 | 
| 2009 | 297 | 96 | 89 | 22 | 4 | 1 | 
| 2010 | 518 | 236 | 24 | 13 | 4 | 1 | 
| 2011 | 280 | 309 | 72 | 4 | 3 | 2 | 
| 2012 | 284 | 190 | 118 | 22 | 1 | 1 | 
| 2013 | 626 | 243 | 104 | 43 | 11 | 2 | 
| 2014 | 737 | 471 | 129 | 48 | 20 | 6 | 
| 2015 | 130 | 601 | 257 | 62 | 27 | 13 |