| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ | 
| 1997 | 11201 | 6337 | 12259 | 1679 | 406 | 179 | 
| 1998 | 10392 | 8819 | 2661 | 2859 | 373 | 114 | 
| 1999 | 8389 | 7733 | 4794 | 725 | 572 | 103 | 
| 2000 | 7996 | 6217 | 3369 | 1299 | 158 | 140 | 
| 2001 | 6332 | 4500 | 2641 | 799 | 247 | 60 | 
| 2002 | 6025 | 3233 | 1434 | 587 | 125 | 56 | 
| 2003 | 4362 | 3824 | 1054 | 318 | 117 | 32 | 
| 2004 | 5692 | 1870 | 1334 | 232 | 73 | 41 | 
| 2005 | 3454 | 2793 | 370 | 276 | 40 | 22 | 
| 2006 | 3108 | 1452 | 829 | 74 | 65 | 15 | 
| 2007 | 1676 | 1185 | 279 | 193 | 19 | 25 | 
| 2008 | 649 | 445 | 208 | 54 | 39 | 9 | 
| 2009 | 1111 | 252 | 63 | 33 | 12 | 7 | 
| 2010 | 1013 | 578 | 47 | 13 | 6 | 3 | 
| 2011 | 1180 | 449 | 102 | 11 | 3 | 2 | 
| 2012 | 1660 | 403 | 58 | 21 | 3 | 1 | 
| 2013 | 2046 | 640 | 80 | 14 | 5 | 1 |