| Year | Count |
|---|---|
| 1978 | 6 |
| 1979 | 7 |
| 1981 | 75 |
| 1982 | 74 |
| 1983 | 61 |
| 1984 | 283 |
| 1985 | 650 |
| 1986 | 889 |
| 1987 | 1,048 |
| 1988 | 1,095 |
| 1989 | 1,537 |
| 1989 | 8 |
| 1990 | 1,373 |
| 1991 | 1,329 |
| 1992 | 953 |
| 1993 | 879 |
| 1994 | 689 |
| 1995 | 529 |
| 1996 | 475 |
| 1997 | 399 |
| 1998 | 336 |
| 1999 | 157 |
| 2000 | 123 |
| 2001 | 43 |
| 2002 | 5 |
| 2003 | 12 |
| 2004 | 20 |
| 2005 | 10 |
| 2006 | 17 |