| Year | Rank | Number |
| 2011 | 5294 | 26 |
| 2010 | 3445 | 47 |
| 2009 | 4869 | 30 |
| 2008 | 3188 | 53 |
| 2007 | 4107 | 38 |
| 2006 | 3491 | 46 |
| 2005 | 3072 | 52 |
| 2004 | 3676 | 40 |
| 2003 | 3118 | 48 |
| 2002 | 3642 | 37 |
| 2001 | 3184 | 44 |
| 2000 | 3866 | 33 |
| 1999 | 3868 | 31 |
| 1998 | 4604 | 24 |
| 1997 | 4345 | 25 |
| 1996 | 5476 | 18 |
| 1995 | 5390 | 18 |
| 1994 | 7494 | 12 |
| 1993 | 5884 | 16 |
| 1992 | 7935 | 11 |
| 1991 | 6509 | 14 |
| 1990 | 12586 | 6 |
| 1989 | 12018 | 6 |