| Year | Rank | Number |
| 2011 | 7602 | 16 |
| 2010 | 10150 | 11 |
| 2009 | 7854 | 16 |
| 2008 | 7229 | 18 |
| 2007 | 7918 | 16 |
| 2006 | 13058 | 8 |
| 2005 | 12488 | 8 |
| 2004 | 8523 | 13 |
| 2003 | 10926 | 9 |
| 2002 | 9203 | 11 |
| 2001 | 12856 | 7 |
| 2000 | 8320 | 12 |
| 1999 | 6081 | 17 |
| 1998 | 10694 | 8 |
| 1997 | 5134 | 20 |
| 1996 | 4969 | 20 |
| 1995 | 5339 | 18 |
| 1994 | 7386 | 12 |
| 1993 | 14767 | 5 |
| 1992 | 7314 | 12 |
| 1991 | 7728 | 11 |
| 1990 | 12248 | 6 |
| 1989 | 9248 | 8 |
| 1988 | 11155 | 6 |
| 1980 | 11345 | 5 |
| 1973 | 9153 | 5 |