| Year | Rank | Number |
| 2011 | 1652 | 129 |
| 2010 | 2229 | 87 |
| 2009 | 2128 | 94 |
| 2008 | 2448 | 78 |
| 2007 | 2559 | 73 |
| 2006 | 2802 | 63 |
| 2005 | 3041 | 53 |
| 2004 | 2841 | 57 |
| 2003 | 3455 | 42 |
| 2002 | 3790 | 35 |
| 2001 | 2374 | 67 |
| 2000 | 3260 | 42 |
| 1999 | 3137 | 42 |
| 1998 | 3164 | 40 |
| 1997 | 3435 | 34 |
| 1996 | 2588 | 49 |
| 1995 | 3074 | 38 |
| 1994 | 3881 | 28 |
| 1993 | 3280 | 35 |
| 1992 | 4362 | 24 |
| 1991 | 4038 | 26 |
| 1990 | 3504 | 31 |
| 1989 | 4501 | 21 |
| 1987 | 7282 | 10 |
| 1986 | 6108 | 12 |
| 1984 | 11937 | 5 |
| 1981 | 8937 | 7 |
| 1979 | 11706 | 5 |