| Year | Rank | Number |
| 2011 | 7480 | 10 |
| 2010 | 6034 | 14 |
| 2009 | 6380 | 13 |
| 2008 | 8332 | 9 |
| 2007 | 6633 | 12 |
| 2006 | 6105 | 13 |
| 2005 | 7647 | 9 |
| 2004 | 6993 | 10 |
| 2003 | 6738 | 10 |
| 2002 | 7063 | 9 |
| 2001 | 8372 | 7 |
| 2000 | 6863 | 9 |
| 1999 | 7174 | 8 |
| 1998 | 5480 | 11 |
| 1996 | 7166 | 7 |
| 1995 | 8939 | 5 |
| 1994 | 7814 | 6 |
| 1993 | 6248 | 8 |
| 1992 | 6698 | 7 |
| 1991 | 5107 | 10 |
| 1990 | 5847 | 8 |
| 1989 | 5642 | 8 |
| 1988 | 7322 | 5 |
| 1987 | 6115 | 6 |
| 1985 | 6569 | 5 |