| Year | Rank | Number |
| 2011 | 15612 | 6 |
| 2010 | 11674 | 9 |
| 2009 | 7125 | 18 |
| 2008 | 12002 | 9 |
| 2007 | 6666 | 20 |
| 2006 | 10192 | 11 |
| 2005 | 7677 | 15 |
| 2004 | 10258 | 10 |
| 2003 | 6416 | 18 |
| 2002 | 11584 | 8 |
| 2001 | 5448 | 21 |
| 2000 | 8255 | 12 |
| 1999 | 13431 | 6 |
| 1998 | 15227 | 5 |
| 1997 | 12819 | 6 |
| 1996 | 9979 | 8 |
| 1995 | 14430 | 5 |
| 1988 | 12657 | 5 |
| 1986 | 10070 | 6 |