| Year | Rank | Number |
| 2010 | 15759 | 6 |
| 2009 | 12865 | 8 |
| 2008 | 14435 | 7 |
| 2007 | 8712 | 14 |
| 2006 | 14176 | 7 |
| 2005 | 13597 | 7 |
| 2004 | 11081 | 9 |
| 2003 | 9977 | 10 |
| 2002 | 10570 | 9 |
| 2001 | 9675 | 10 |
| 2000 | 11170 | 8 |
| 1999 | 10759 | 8 |
| 1998 | 13120 | 6 |
| 1997 | 14703 | 5 |
| 1996 | 11045 | 7 |
| 1994 | 14346 | 5 |
| 1992 | 9866 | 8 |
| 1989 | 10152 | 7 |
| 1988 | 12578 | 5 |
| 1987 | 10382 | 6 |
| 1985 | 7855 | 8 |
| 1984 | 11060 | 5 |
| 1979 | 9420 | 6 |