| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ |
| 1997 | 17459 | 6226 | 9133 | 1448 | 326 | 134 |
| 1998 | 13647 | 11898 | 2779 | 2710 | 376 | 113 |
| 1999 | 12951 | 8989 | 5793 | 718 | 582 | 107 |
| 2000 | 7412 | 8494 | 3683 | 1411 | 163 | 147 |
| 2001 | 6587 | 4497 | 3168 | 850 | 266 | 61 |
| 2002 | 12840 | 4088 | 1726 | 718 | 145 | 61 |
| 2003 | 3055 | 7638 | 1529 | 463 | 191 | 49 |
| 2004 | 15169 | 1986 | 2546 | 397 | 135 | 76 |
| 2005 | 6888 | 7875 | 451 | 538 | 73 | 39 |
| 2006 | 8280 | 4046 | 2444 | 139 | 158 | 35 |
| 2007 | 2145 | 3778 | 972 | 543 | 47 | 69 |
| 2008 | 1160 | 711 | 468 | 149 | 97 | 23 |
| 2009 | 3568 | 448 | 116 | 87 | 27 | 19 |
| 2010 | 3123 | 1645 | 119 | 32 | 16 | 8 |
| 2011 | 3615 | 1542 | 453 | 35 | 9 | 6 |
| 2012 | 8756 | 1837 | 370 | 152 | 16 | 6 |
| 2013 | 10615 | 4166 | 657 | 174 | 60 | 11 |
| 2014 | 4090 | 6126 | 1415 | 367 | 101 | 40 |
| 2015 | 3167 | 1881 | 2257 | 867 | 233 | 90 |
| 2016 | 983 | 1402 | 774 | 940 | 430 | 166 |
| 2017 | 5542 | 623 | 574 | 307 | 327 | 197 |
| 2018 | 577 | 2039 | 123 | 193 | 99 | 145 |
| 2019 | 1363 | 283 | 340 | 32 | 35 | 27 |
| 2020 | 2682 | 663 | 39 | 72 | 3 | 8 |
| 2021 | 1003 | 910 | 90 | 7 | 19 | 2 |
| 2022 | 2180 | 374 | 83 | 15 | 2 | 6 |
| 2023 | 3617 | 888 | 56 | 18 | 2 | 1 |