| Year | Rank | Number |
| 2011 | 8741 | 13 |
| 2010 | 12663 | 8 |
| 2009 | 11717 | 9 |
| 2008 | 10288 | 11 |
| 2007 | 9730 | 12 |
| 2006 | 6423 | 20 |
| 2005 | 4992 | 26 |
| 2004 | 6307 | 19 |
| 2003 | 5648 | 21 |
| 2002 | 4670 | 26 |
| 2001 | 4882 | 24 |
| 2000 | 3907 | 32 |
| 1999 | 6611 | 15 |
| 1998 | 11558 | 7 |
| 1997 | 9294 | 9 |
| 1996 | 7765 | 11 |
| 1995 | 6063 | 15 |
| 1994 | 6097 | 15 |
| 1993 | 8273 | 10 |
| 1992 | 8286 | 10 |
| 1991 | 8842 | 9 |
| 1988 | 10814 | 6 |
| 1987 | 10295 | 6 |