| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 0 | 1 | 2 | 3 | 4 | 5+ | 
| 1991 | 110747 | 57354 | 34441 | 13865 | 1369 | 2739 | 
| 1992 | 2264 | 35739 | 49662 | 24441 | 3667 | 1140 | 
| 1993 | 54776 | 3468 | 14111 | 16943 | 11104 | 4370 | 
| 1994 | 85905 | 19497 | 2858 | 6778 | 4121 | 3471 | 
| 1995 | 61574 | 27228 | 11853 | 2684 | 1861 | 1738 | 
| 1996 | 16838 | 45433 | 8383 | 2434 | 1783 | 756 | 
| 1997 | 60901 | 14432 | 17441 | 8313 | 1427 | 358 | 
| 1998 | 24270 | 8929 | 7025 | 3945 | 1059 | 584 | 
| 1999 | 50362 | 3900 | 4737 | 5051 | 1407 | 767 | 
| 2000 | 42404 | 51637 | 6320 | 3188 | 1254 | 327 | 
| 2001 | 85221 | 25109 | 24810 | 2623 | 1604 | 800 | 
| 2002 | 157314 | 102130 | 11499 | 4325 | 625 | 519 | 
| 2003 | 271034 | 141634 | 45297 | 6085 | 1051 | 152 | 
| 2004 | 40864 | 171613 | 68528 | 13885 | 1483 | 2251 | 
| 2005 | 22292 | 17928 | 112308 | 16173 | 4703 | 383 | 
| 2006 | 39577 | 50767 | 25135 | 40417 | 7791 | 3389 | 
| 2007 | 72693 | 33523 | 34996 | 13653 | 17640 | 6454 | 
| 2008 | 102847 | 44578 | 20402 | 8923 | 6858 | 3996 | 
| 2009 | 149792 | 80822 | 21699 | 8034 | 4297 | 4496 | 
| 2010 | 100609 | 112984 | 24835 | 5686 | 3022 | 1981 | 
| 2011 | 118302 | 117125 | 38484 | 10048 | 1966 | 539 | 
| 2012 | 46397 | 166043 | 55271 | 18579 | 3436 | 1784 | 
| 2013 | 176310 | 36938 | 76267 | 29941 | 8071 | 2599 | 
| 2014 | 65513 | 308353 | 44091 | 34752 | 13616 | 4622 |