| Year | Rank | Number |
| 2011 | 13369 | 5 |
| 2010 | 11551 | 6 |
| 2009 | 7433 | 11 |
| 2008 | 9473 | 8 |
| 2007 | 11723 | 6 |
| 2006 | 10171 | 7 |
| 2005 | 8748 | 8 |
| 2004 | 12398 | 5 |
| 2003 | 11948 | 5 |
| 2002 | 8987 | 7 |
| 2001 | 8817 | 7 |
| 2000 | 9790 | 6 |
| 1999 | 9381 | 6 |
| 1998 | 6602 | 9 |
| 1997 | 5899 | 10 |
| 1996 | 8532 | 6 |
| 1995 | 8402 | 6 |
| 1994 | 8330 | 6 |
| 1993 | 6016 | 9 |
| 1992 | 9205 | 5 |
| 1990 | 4295 | 13 |
| 1989 | 7484 | 6 |
| 1988 | 7961 | 5 |
| 1982 | 6907 | 5 |