| Year | Rank | Number |
| 2011 | 3086 | 37 |
| 2010 | 2997 | 39 |
| 2009 | 2557 | 49 |
| 2008 | 3085 | 38 |
| 2007 | 2849 | 42 |
| 2006 | 3069 | 36 |
| 2005 | 4165 | 22 |
| 2004 | 6462 | 12 |
| 2003 | 6197 | 12 |
| 2002 | 6023 | 12 |
| 2001 | 4442 | 18 |
| 2000 | 5534 | 13 |
| 1999 | 8591 | 7 |
| 1998 | 8347 | 7 |
| 1997 | 9123 | 6 |
| 1996 | 6430 | 9 |
| 1994 | 8662 | 6 |
| 1993 | 7519 | 7 |
| 1992 | 7301 | 7 |
| 1990 | 6335 | 8 |
| 1989 | 9076 | 5 |
| 1988 | 8345 | 5 |