| Year | Rank | Number |
| 2011 | 9889 | 11 |
| 2010 | 5477 | 25 |
| 2009 | 7743 | 16 |
| 2008 | 6389 | 21 |
| 2007 | 7484 | 17 |
| 2006 | 5582 | 24 |
| 2005 | 5484 | 23 |
| 2004 | 10996 | 9 |
| 2003 | 5879 | 20 |
| 2002 | 5131 | 23 |
| 2001 | 6427 | 17 |
| 2000 | 5552 | 20 |
| 1999 | 5741 | 18 |
| 1998 | 6160 | 16 |
| 1997 | 9291 | 9 |
| 1996 | 4925 | 20 |
| 1995 | 6773 | 13 |
| 1994 | 5536 | 17 |
| 1993 | 6385 | 14 |
| 1992 | 6110 | 15 |
| 1991 | 7587 | 11 |
| 1990 | 11889 | 6 |
| 1989 | 11312 | 6 |
| 1988 | 12449 | 5 |