| Year | Rank | Number |
| 2011 | 13031 | 5 |
| 2010 | 11297 | 6 |
| 2009 | 9272 | 8 |
| 2008 | 11643 | 6 |
| 2007 | 10218 | 7 |
| 2006 | 5897 | 14 |
| 2005 | 5994 | 13 |
| 2004 | 10511 | 6 |
| 2003 | 5686 | 13 |
| 2002 | 9921 | 6 |
| 2001 | 6189 | 11 |
| 2000 | 5716 | 12 |
| 1999 | 8219 | 7 |
| 1998 | 7936 | 7 |
| 1997 | 6871 | 8 |
| 1996 | 6196 | 9 |
| 1995 | 4375 | 14 |
| 1994 | 9429 | 5 |
| 1993 | 6465 | 8 |
| 1992 | 6986 | 7 |
| 1991 | 8758 | 5 |
| 1987 | 7452 | 5 |
| 1986 | 5568 | 7 |
| 1981 | 6692 | 5 |
| 1972 | 4682 | 6 |