| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ |
| 2005 | 17680979 | 14490445 | 8137552 | 3285403 | 1047587 | 273484 | 272393 |
| 2006 | 18550365 | 14887016 | 8351903 | 3375318 | 1085987 | 279568 | 275406 |
| 2007 | 20095370 | 16288990 | 8930652 | 3569728 | 1140526 | 300139 | 294490 |
| 2008 | 19599214 | 16223965 | 8930652 | 3548374 | 1129177 | 292728 | 290686 |
| 2009 | 19134432 | 15728737 | 8868356 | 3513067 | 1113479 | 285501 | 284930 |
| 2010 | 20542367 | 16337931 | 9101957 | 3649132 | 1154295 | 298642 | 294196 |
| 2011 | 20542367 | 17158427 | 9520901 | 3828563 | 1225672 | 315212 | 307429 |
| 2012 | 20460362 | 17038738 | 9703527 | 3894205 | 1236753 | 321901 | 318698 |
| 2013 | 20583493 | 16601440 | 9369778 | 3817094 | 1217122 | 309589 | 308970 |
| 2014 | 22499418 | 17805180 | 9752166 | 3898101 | 1236753 | 322868 | 315212 |