| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 1 | 2 | 3 | 4 | 5 | 6+ | 
| 1997 | 15558 | 6509 | 10294 | 1631 | 384 | 173 | 
| 1998 | 12559 | 11368 | 2847 | 2703 | 388 | 108 | 
| 1999 | 10810 | 8861 | 5589 | 704 | 586 | 101 | 
| 2000 | 8375 | 7530 | 3730 | 1350 | 163 | 140 | 
| 2001 | 5889 | 4532 | 2913 | 821 | 253 | 61 | 
| 2002 | 8209 | 3208 | 1407 | 611 | 131 | 60 | 
| 2003 | 4491 | 5241 | 1169 | 340 | 143 | 39 | 
| 2004 | 11367 | 2317 | 2040 | 315 | 99 | 62 | 
| 2005 | 7617 | 6855 | 694 | 611 | 87 | 49 | 
| 2006 | 9632 | 3759 | 2418 | 179 | 173 | 44 | 
| 2007 | 5064 | 3580 | 845 | 609 | 54 | 78 | 
| 2008 | 1998 | 1467 | 790 | 219 | 152 | 34 | 
| 2009 | 7182 | 949 | 264 | 157 | 59 | 31 | 
| 2010 | 5371 | 3917 | 235 | 66 | 34 | 17 | 
| 2011 | 7199 | 2708 | 789 | 67 | 19 | 11 | 
| 2012 | 13314 | 2883 | 420 | 198 | 26 | 9 | 
| 2013 | 15343 | 5348 | 743 | 122 | 55 | 13 | 
| 2014 | 4245 | 6420 | 1398 | 232 | 38 | 25 |