| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ | 
| 1997 | 13963 | 6730 | 10160 | 1524 | 369 | 170 | 
| 1998 | 12038 | 11492 | 2772 | 2727 | 386 | 110 | 
| 1999 | 10230 | 8442 | 5376 | 618 | 563 | 103 | 
| 2000 | 7753 | 7683 | 3460 | 1388 | 173 | 147 | 
| 2001 | 4379 | 3748 | 2587 | 832 | 276 | 72 | 
| 2002 | 5892 | 2441 | 1081 | 604 | 160 | 78 | 
| 2003 | 2714 | 4292 | 878 | 285 | 163 | 44 | 
| 2004 | 7751 | 1898 | 1914 | 320 | 148 | 107 | 
| 2005 | 3396 | 4106 | 345 | 446 | 86 | 52 | 
| 2006 | 5109 | 2241 | 1636 | 129 | 169 | 52 | 
| 2007 | 2937 | 1945 | 520 | 526 | 67 | 105 | 
| 2008 | 694 | 478 | 340 | 142 | 149 | 43 | 
| 2009 | 2328 | 251 | 88 | 111 | 73 | 40 | 
| 2010 | 1568 | 1570 | 98 | 48 | 51 | 32 | 
| 2011 | 2366 | 1035 | 503 | 53 | 30 | 19 | 
| 2012 | 3422 | 791 | 183 | 195 | 38 | 19 | 
| 2013 | 4254 | 1909 | 434 | 93 | 85 | 28 | 
| 2014 | 1185 | 3973 | 1014 | 288 | 59 | 49 |