| Year | Rank | Number |
| 2011 | 18061 | 5 |
| 2010 | 14178 | 7 |
| 2008 | 8295 | 15 |
| 2007 | 12109 | 9 |
| 2006 | 16089 | 6 |
| 2005 | 15422 | 6 |
| 2004 | 9550 | 11 |
| 2003 | 11836 | 8 |
| 2002 | 11611 | 8 |
| 2001 | 8458 | 12 |
| 2000 | 6976 | 15 |
| 1999 | 9130 | 10 |
| 1996 | 10017 | 8 |
| 1995 | 8395 | 10 |
| 1994 | 11092 | 7 |
| 1993 | 10021 | 8 |
| 1992 | 9916 | 8 |
| 1991 | 10824 | 7 |
| 1990 | 9670 | 8 |
| 1989 | 5407 | 16 |
| 1988 | 6046 | 13 |
| 1987 | 4944 | 16 |
| 1986 | 5302 | 14 |
| 1985 | 5817 | 12 |
| 1984 | 4589 | 16 |
| 1983 | 11031 | 5 |
| 1982 | 7149 | 9 |
| 1981 | 8496 | 7 |
| 1978 | 9031 | 6 |