| Year | Rank | Number |
| 2011 | 11801 | 6 |
| 2009 | 9549 | 8 |
| 2008 | 14040 | 5 |
| 2007 | 11949 | 6 |
| 2006 | 7843 | 10 |
| 2005 | 9848 | 7 |
| 2004 | 7991 | 9 |
| 2003 | 5792 | 13 |
| 2002 | 6400 | 11 |
| 2001 | 6323 | 11 |
| 2000 | 7246 | 9 |
| 1999 | 6378 | 10 |
| 1998 | 6692 | 9 |
| 1997 | 6472 | 9 |
| 1996 | 7728 | 7 |
| 1995 | 8588 | 6 |
| 1994 | 8514 | 6 |
| 1993 | 6089 | 9 |
| 1992 | 8173 | 6 |
| 1991 | 5810 | 9 |
| 1990 | 5686 | 9 |
| 1988 | 4375 | 11 |
| 1985 | 5576 | 7 |
| 1984 | 5412 | 7 |
| 1982 | 7068 | 5 |
| 1980 | 6992 | 5 |
| 1977 | 5651 | 6 |