| Year | Rank | Number |
| 2011 | 5720 | 23 |
| 2010 | 6401 | 20 |
| 2009 | 4778 | 30 |
| 2008 | 5013 | 29 |
| 2007 | 4693 | 31 |
| 2006 | 7534 | 16 |
| 2005 | 5617 | 22 |
| 2004 | 5080 | 25 |
| 2003 | 6346 | 18 |
| 2002 | 10355 | 9 |
| 2001 | 13781 | 6 |
| 2000 | 15415 | 5 |
| 1999 | 14754 | 5 |
| 1998 | 8674 | 10 |
| 1997 | 12308 | 6 |
| 1994 | 8913 | 9 |
| 1993 | 9677 | 8 |
| 1992 | 13567 | 5 |
| 1977 | 8561 | 6 |
| 1974 | 6975 | 7 |