| Year | Rank | Number |
| 2011 | 12718 | 8 |
| 2010 | 15984 | 6 |
| 2009 | 14394 | 7 |
| 2008 | 10423 | 11 |
| 2007 | 9841 | 12 |
| 2006 | 11023 | 10 |
| 2005 | 13760 | 7 |
| 2004 | 10313 | 10 |
| 2003 | 10072 | 10 |
| 2002 | 9893 | 10 |
| 2001 | 7537 | 14 |
| 2000 | 6345 | 17 |
| 1999 | 15697 | 5 |
| 1998 | 15390 | 5 |
| 1997 | 8712 | 10 |
| 1996 | 6933 | 13 |
| 1995 | 8421 | 10 |
| 1994 | 5135 | 19 |
| 1993 | 9123 | 9 |
| 1992 | 14401 | 5 |
| 1990 | 9711 | 8 |
| 1989 | 10275 | 7 |
| 1987 | 9280 | 7 |
| 1986 | 8101 | 8 |
| 1984 | 8614 | 7 |