| Year | Rank | Number |
| 2011 | 3404 | 32 |
| 2010 | 2816 | 43 |
| 2009 | 4700 | 21 |
| 2008 | 3546 | 31 |
| 2007 | 2805 | 43 |
| 2006 | 2874 | 40 |
| 2005 | 2357 | 50 |
| 2004 | 3151 | 32 |
| 2003 | 2543 | 41 |
| 2002 | 2878 | 33 |
| 2001 | 3967 | 21 |
| 2000 | 3634 | 23 |
| 1999 | 5023 | 14 |
| 1998 | 4639 | 15 |
| 1997 | 4664 | 14 |
| 1996 | 5525 | 11 |
| 1995 | 7779 | 7 |
| 1994 | 6954 | 8 |
| 1992 | 8412 | 6 |
| 1991 | 8218 | 6 |
| 1990 | 9470 | 5 |
| 1989 | 7893 | 6 |
| 1988 | 7248 | 6 |
| 1987 | 6936 | 6 |
| 1986 | 5904 | 7 |
| 1985 | 7562 | 5 |
| 1983 | 7317 | 5 |
| 1981 | 4487 | 9 |
| 1980 | 6232 | 6 |
| 1978 | 5758 | 6 |