| Year | Rank | Number |
| 2011 | 10651 | 10 |
| 2010 | 14105 | 7 |
| 2009 | 8563 | 14 |
| 2008 | 8279 | 15 |
| 2007 | 7210 | 18 |
| 2006 | 4718 | 30 |
| 2005 | 7669 | 15 |
| 2004 | 5122 | 25 |
| 2003 | 4248 | 31 |
| 2002 | 3751 | 35 |
| 2001 | 4366 | 28 |
| 2000 | 12368 | 7 |
| 1998 | 7300 | 13 |
| 1997 | 7470 | 12 |
| 1996 | 5153 | 19 |
| 1995 | 7749 | 11 |
| 1994 | 9141 | 9 |
| 1993 | 14438 | 5 |
| 1990 | 13914 | 5 |
| 1989 | 11423 | 6 |
| 1984 | 9606 | 6 |
| 1980 | 7016 | 9 |
| 1979 | 7579 | 8 |
| 1978 | 7974 | 7 |
| 1977 | 10257 | 5 |