| Year | Rank | Number |
| 2011 | 4398 | 22 |
| 2010 | 5862 | 15 |
| 2009 | 4320 | 23 |
| 2008 | 3514 | 31 |
| 2007 | 4061 | 25 |
| 2006 | 3554 | 29 |
| 2005 | 3570 | 27 |
| 2004 | 3684 | 25 |
| 2003 | 3019 | 32 |
| 2002 | 3220 | 28 |
| 2001 | 4206 | 19 |
| 2000 | 4130 | 19 |
| 1999 | 4645 | 15 |
| 1998 | 4519 | 15 |
| 1997 | 3109 | 24 |
| 1996 | 3921 | 17 |
| 1995 | 3960 | 16 |
| 1994 | 5663 | 10 |
| 1993 | 4852 | 12 |
| 1992 | 5433 | 10 |
| 1991 | 7739 | 6 |