| Year | Rank | Number |
| 2011 | 9696 | 11 |
| 2010 | 6166 | 21 |
| 2009 | 10637 | 10 |
| 2008 | 10099 | 11 |
| 2007 | 12728 | 8 |
| 2006 | 6856 | 18 |
| 2005 | 7519 | 15 |
| 2004 | 8753 | 12 |
| 2003 | 6067 | 19 |
| 2002 | 6138 | 18 |
| 2001 | 7753 | 13 |
| 2000 | 5154 | 22 |
| 1999 | 6207 | 16 |
| 1998 | 3921 | 29 |
| 1997 | 4376 | 24 |
| 1996 | 4586 | 22 |
| 1995 | 4350 | 23 |
| 1994 | 4847 | 20 |
| 1993 | 5968 | 15 |
| 1992 | 3870 | 27 |
| 1991 | 3633 | 29 |
| 1990 | 3912 | 26 |
| 1989 | 5844 | 14 |
| 1988 | 4310 | 20 |
| 1987 | 5928 | 12 |