| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 0 | 1 | 2 | 3 | 4 | 5+ | 
| 1991 | 41815 | 64926 | 57642 | 17654 | 1380 | 2837 | 
| 1992 | 13582 | 26903 | 35454 | 24101 | 5868 | 1201 | 
| 1993 | 28970 | 8791 | 14644 | 14602 | 8003 | 2027 | 
| 1994 | 36498 | 18559 | 4829 | 6037 | 4762 | 2796 | 
| 1995 | 37760 | 23202 | 10073 | 2016 | 1975 | 2073 | 
| 1996 | 25489 | 24173 | 12494 | 4095 | 672 | 1104 | 
| 1997 | 20040 | 16477 | 12956 | 5064 | 1348 | 487 | 
| 1998 | 13911 | 12874 | 8959 | 5155 | 1641 | 514 | 
| 1999 | 34648 | 9015 | 7006 | 3630 | 1668 | 609 | 
| 2000 | 28029 | 23389 | 4904 | 2828 | 1193 | 643 | 
| 2001 | 96955 | 19063 | 12690 | 1945 | 938 | 533 | 
| 2002 | 135402 | 68050 | 10233 | 4983 | 640 | 427 | 
| 2003 | 142059 | 95511 | 37086 | 4057 | 1658 | 312 | 
| 2004 | 49911 | 101620 | 51948 | 14694 | 1367 | 602 | 
| 2005 | 54885 | 36026 | 55603 | 20382 | 5078 | 585 | 
| 2006 | 51483 | 40255 | 20032 | 21770 | 7117 | 1714 | 
| 2007 | 56783 | 37534 | 22315 | 8047 | 7591 | 2636 | 
| 2008 | 65578 | 40987 | 20742 | 8970 | 2952 | 3011 | 
| 2009 | 100710 | 48050 | 22584 | 8442 | 3335 | 1870 | 
| 2010 | 123624 | 74087 | 26423 | 9139 | 3158 | 1713 | 
| 2011 | 159532 | 92042 | 40946 | 10764 | 3415 | 1676 | 
| 2012 | 90944 | 118421 | 51124 | 17028 | 4061 | 1828 | 
| 2013 | 224134 | 68391 | 65382 | 21254 | 6513 | 2165 | 
| 2014 | 108445 | 172301 | 38254 | 26984 | 8106 | 3210 | 
| 2015 | 90762 | 81716 | 97441 | 15934 | 10119 | 4081 | 
| 2016 | 66769 | 68734 | 45752 | 40864 | 6029 | 5102 |