| Table 2. Estimated stock numbers. | |||||||
| Year\Age | 2 | 3 | 4 | 5 | 6 | 7 | 8+ |
| 2005 | 17751845 | 14563078 | 8153844 | 3291981 | 1047587 | 273484 | 272393 |
| 2006 | 18643349 | 14946684 | 8368624 | 3378695 | 1085987 | 279568 | 275406 |
| 2007 | 20196098 | 16370639 | 8948532 | 3573300 | 1140526 | 300139 | 294490 |
| 2008 | 19697455 | 16305288 | 8948532 | 3555478 | 1129177 | 292728 | 290686 |
| 2009 | 19211123 | 15807578 | 8877229 | 3516582 | 1113479 | 285501 | 284930 |
| 2010 | 20624701 | 16419825 | 9111063 | 3656438 | 1154295 | 298642 | 294196 |
| 2011 | 20624701 | 17244434 | 9539961 | 3832393 | 1225672 | 315212 | 307429 |
| 2012 | 20562920 | 17107029 | 9722954 | 3902001 | 1236753 | 321901 | 318698 |
| 2013 | 20665992 | 16684655 | 9388537 | 3824736 | 1217122 | 309589 | 308970 |
| 2014 | 22589596 | 17876544 | 9771690 | 3902001 | 1236753 | 322868 | 315212 |