| Year | Count |
|---|---|
| 1974 | 5 |
| 1975 | 6 |
| 1977 | 5 |
| 1978 | 7 |
| 1979 | 6 |
| 1980 | 5 |
| 1980 | 15 |
| 1981 | 13 |
| 1982 | 5 |
| 1982 | 20 |
| 1983 | 24 |
| 1984 | 39 |
| 1985 | 161 |
| 1986 | 191 |
| 1987 | 315 |
| 1988 | 15 |
| 1988 | 412 |
| 1989 | 389 |
| 1990 | 513 |
| 1991 | 5 |
| 1991 | 615 |
| 1992 | 760 |
| 1993 | 20 |
| 1993 | 515 |
| 1994 | 354 |
| 1995 | 269 |
| 1996 | 186 |
| 1997 | 131 |
| 1998 | 45 |
| 1999 | 34 |
| 2000 | 19 |
| 2001 | 11 |
| 2002 | 10 |