| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ |
| 1997 | 17520 | 6203 | 9123 | 1446 | 325 | 133 |
| 1998 | 13680 | 11980 | 2779 | 2694 | 373 | 112 |
| 1999 | 12974 | 9010 | 5781 | 717 | 580 | 106 |
| 2000 | 7418 | 8510 | 3685 | 1406 | 162 | 147 |
| 2001 | 6547 | 4510 | 3177 | 845 | 266 | 61 |
| 2002 | 12804 | 4057 | 1722 | 721 | 146 | 61 |
| 2003 | 2996 | 7583 | 1504 | 457 | 190 | 49 |
| 2004 | 15189 | 1935 | 2509 | 389 | 133 | 75 |
| 2005 | 6776 | 7871 | 450 | 534 | 72 | 39 |
| 2006 | 8139 | 3945 | 2396 | 137 | 156 | 35 |
| 2007 | 2103 | 3697 | 940 | 530 | 46 | 67 |
| 2008 | 1103 | 703 | 461 | 145 | 96 | 22 |
| 2009 | 3500 | 435 | 114 | 86 | 26 | 19 |
| 2010 | 3046 | 1617 | 116 | 32 | 16 | 8 |
| 2011 | 3722 | 1499 | 445 | 34 | 9 | 6 |
| 2012 | 8717 | 1843 | 365 | 150 | 15 | 6 |
| 2013 | 10774 | 4101 | 649 | 170 | 60 | 11 |
| 2014 | 3930 | 5993 | 1382 | 358 | 98 | 40 |
| 2015 | 3031 | 1800 | 2166 | 828 | 223 | 86 |
| 2016 | 888 | 1351 | 737 | 905 | 411 | 158 |
| 2017 | 5357 | 566 | 547 | 294 | 317 | 191 |
| 2018 | 569 | 1976 | 116 | 187 | 94 | 141 |
| 2019 | 1279 | 273 | 331 | 31 | 34 | 27 |
| 2020 | 2568 | 625 | 38 | 72 | 3 | 8 |
| 2021 | 918 | 888 | 91 | 7 | 19 | 2 |
| 2022 | 1730 | 334 | 84 | 17 | 2 | 6 |
| 2023 | 6780 | 646 | 58 | 25 | 4 | 2 |
| 2024 | 1981 | 2988 | 130 | 20 | 6 | 1 |