| Year | Rank | Number |
| 2010 | 9636 | 12 |
| 2009 | 19404 | 5 |
| 2008 | 8841 | 14 |
| 2007 | 15085 | 7 |
| 2006 | 19339 | 5 |
| 2005 | 14147 | 7 |
| 2002 | 13295 | 7 |
| 2000 | 16980 | 5 |
| 1999 | 14009 | 6 |
| 1996 | 9393 | 9 |
| 1995 | 12982 | 6 |
| 1994 | 13018 | 6 |
| 1992 | 14956 | 5 |
| 1986 | 10520 | 6 |
| 1985 | 10285 | 6 |
| 1984 | 11676 | 5 |
| 1982 | 8930 | 7 |
| 1977 | 10815 | 5 |
| 1975 | 10169 | 5 |
| 1972 | 9250 | 5 |
| 1968 | 6809 | 6 |