| Year | Rank | Number |
| 2011 | 14280 | 7 |
| 2010 | 18926 | 5 |
| 2009 | 16516 | 6 |
| 2008 | 11303 | 10 |
| 2006 | 12096 | 9 |
| 2005 | 15827 | 6 |
| 2004 | 7699 | 15 |
| 2003 | 8890 | 12 |
| 2002 | 13191 | 7 |
| 2001 | 7608 | 14 |
| 2000 | 5623 | 20 |
| 1999 | 6115 | 17 |
| 1998 | 7404 | 13 |
| 1997 | 7599 | 12 |
| 1996 | 7445 | 12 |
| 1995 | 11353 | 7 |
| 1994 | 12900 | 6 |
| 1993 | 9266 | 9 |
| 1992 | 7862 | 11 |
| 1991 | 12566 | 6 |
| 1990 | 7680 | 11 |
| 1989 | 9351 | 8 |
| 1988 | 6137 | 13 |
| 1987 | 7787 | 9 |
| 1986 | 10426 | 6 |