| Table 2. Estimated stock numbers. | ||||||||
| Year\Age | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7+ |
| 1977 | 184241 | 157945 | 41357 | 5160 | 3249 | 415 | 156 | 156 |
| 1978 | 124617 | 84626 | 66304 | 8186 | 1298 | 988 | 165 | 107 |
| 1979 | 214701 | 53210 | 37384 | 14565 | 2130 | 452 | 404 | 120 |
| 1980 | 154353 | 101114 | 21818 | 10019 | 3492 | 670 | 159 | 180 |
| 1981 | 154508 | 68118 | 45890 | 5420 | 2547 | 978 | 217 | 111 |
| 1982 | 195048 | 68597 | 30152 | 12127 | 1327 | 757 | 296 | 110 |
| 1983 | 65121 | 94183 | 30031 | 8624 | 2722 | 424 | 255 | 124 |
| 1984 | 48972 | 28001 | 44489 | 8386 | 2092 | 702 | 138 | 121 |
| 1985 | 93807 | 20906 | 12417 | 12187 | 1932 | 545 | 214 | 87 |
| 1986 | 35348 | 46074 | 9590 | 3735 | 2435 | 415 | 151 | 82 |
| 1987 | 13211 | 15886 | 23671 | 3152 | 806 | 490 | 106 | 61 |
| 1988 | 15234 | 5583 | 8129 | 8412 | 759 | 180 | 131 | 47 |
| 1989 | 25362 | 6710 | 2595 | 3181 | 2095 | 190 | 52 | 50 |
| 1990 | 48972 | 11308 | 3582 | 1049 | 883 | 542 | 62 | 32 |
| 1991 | 78198 | 22248 | 6441 | 1421 | 269 | 224 | 170 | 32 |
| 1992 | 25591 | 38292 | 12722 | 2474 | 335 | 57 | 61 | 55 |
| 1993 | 67306 | 10515 | 23156 | 5682 | 618 | 67 | 10 | 26 |
| 1994 | 101926 | 31257 | 7185 | 11825 | 1714 | 123 | 13 | 8 |
| 1995 | 21775 | 50212 | 21993 | 3587 | 3553 | 547 | 28 | 4 |
| 1996 | 82702 | 9248 | 38677 | 10489 | 849 | 1024 | 125 | 5 |
| 1997 | 150995 | 38793 | 5103 | 19258 | 2068 | 206 | 241 | 36 |
| 1998 | 46911 | 71539 | 24959 | 2306 | 4248 | 460 | 59 | 73 |
| 1999 | 49811 | 19958 | 46120 | 10727 | 563 | 895 | 129 | 41 |
| 2000 | 42193 | 22449 | 12823 | 19378 | 2391 | 116 | 213 | 42 |
| 2001 | 70263 | 18464 | 15373 | 5274 | 3633 | 556 | 30 | 63 |
| 2002 | 24514 | 33456 | 11986 | 6535 | 1051 | 742 | 150 | 21 |
| 2003 | 60054 | 9976 | 23318 | 5009 | 1219 | 228 | 183 | 44 |
| 2004 | 19693 | 29644 | 5960 | 9968 | 1081 | 250 | 61 | 56 |
| 2005 | 18095 | 8403 | 22315 | 2616 | 1962 | 222 | 50 | 24 |
| 2006 | 7561 | 8446 | 5868 | 11212 | 637 | 321 | 38 | 12 |
| 2007 | 3679 | 3420 | 6040 | 2886 | 2391 | 151 | 35 | 6 |
| 2008 | 27310 | 1455 | 2387 | 2659 | 564 | 394 | 33 | 7 |
| 2009 | 12549 | 13819 | 1116 | 1410 | 426 | 88 | 52 | 7 |
| 2010 | 14226 | 5403 | 12090 | 654 | 267 | 47 | 12 | 6 |
| 2011 | 11237 | 6389 | 3701 | 7367 | 115 | 44 | 7 | 4 |
| 2012 | 25286 | 4778 | 4326 | 1825 | 1494 | 24 | 10 | 2 |
| 2013 | 27065 | 11513 | 3535 | 2420 | 322 | 276 | 5 | 3 |
| 2014 | 27065 | 12018 | 8104 | 1846 | 426 | 61 | 65 | 2 |