| Table 2. Estimated stock numbers. | ||||||
| Year\Age | 0 | 1 | 2 | 3 | 4 | 5+ |
| 1991 | 328404 | 280127 | 201390 | 96664 | 47005 | 124119 |
| 1992 | 256786 | 230268 | 179692 | 131795 | 63070 | 121419 |
| 1993 | 315843 | 186652 | 142486 | 113664 | 87466 | 130744 |
| 1994 | 346279 | 224808 | 119372 | 89949 | 73497 | 151146 |
| 1995 | 371016 | 246718 | 142629 | 78984 | 59042 | 157629 |
| 1996 | 347319 | 271577 | 157945 | 93807 | 54940 | 157787 |
| 1997 | 352568 | 250446 | 169058 | 102232 | 63196 | 152665 |
| 1998 | 345242 | 252206 | 158578 | 107366 | 67846 | 155749 |
| 1999 | 423369 | 252963 | 161458 | 105240 | 72766 | 164555 |
| 2000 | 416649 | 312388 | 163407 | 106724 | 72258 | 174730 |
| 2001 | 516588 | 303155 | 197008 | 106831 | 72839 | 180232 |
| 2002 | 614153 | 389648 | 194075 | 125995 | 73792 | 186279 |
| 2003 | 771429 | 455887 | 249197 | 125116 | 84036 | 186839 |
| 2004 | 519696 | 587717 | 298343 | 162592 | 86942 | 202400 |
| 2005 | 531256 | 382315 | 392778 | 191952 | 110857 | 209819 |
| 2006 | 597196 | 410446 | 260146 | 263024 | 135266 | 242802 |
| 2007 | 597793 | 438011 | 271848 | 174556 | 182408 | 275681 |
| 2008 | 699415 | 449100 | 288659 | 182408 | 123748 | 334035 |
| 2009 | 814231 | 522824 | 296262 | 193687 | 128412 | 338067 |
| 2010 | 872397 | 611090 | 339083 | 197205 | 135537 | 342833 |
| 2011 | 934718 | 660003 | 397520 | 223686 | 136489 | 349060 |
| 2012 | 817495 | 717121 | 440647 | 267801 | 155438 | 361494 |
| 2013 | 1078412 | 619086 | 477825 | 300740 | 188905 | 389259 |
| 2014 | 958380 | 819951 | 407176 | 320296 | 210449 | 426770 |