| Year | Rank | Number |
| 2008 | 18357 | 5 |
| 2007 | 18494 | 5 |
| 2006 | 15733 | 6 |
| 2005 | 12180 | 8 |
| 2004 | 13178 | 7 |
| 2003 | 14439 | 6 |
| 2001 | 9604 | 10 |
| 1999 | 10665 | 8 |
| 1997 | 14473 | 5 |
| 1996 | 10944 | 7 |
| 1994 | 9057 | 9 |
| 1993 | 8952 | 9 |
| 1992 | 10841 | 7 |
| 1991 | 11986 | 6 |
| 1990 | 7003 | 12 |
| 1988 | 10778 | 6 |
| 1987 | 7557 | 9 |
| 1986 | 8827 | 7 |
| 1985 | 9675 | 6 |
| 1983 | 9394 | 6 |
| 1982 | 7690 | 8 |
| 1981 | 9442 | 6 |
| 1980 | 9431 | 6 |
| 1977 | 10105 | 5 |
| 1973 | 8832 | 5 |