| Year | Count |
|---|---|
| 1970 | 12 |
| 1972 | 5 |
| 1973 | 10 |
| 1974 | 22 |
| 1975 | 5 |
| 1976 | 5 |
| 1977 | 6 |
| 1978 | 29 |
| 1979 | 43 |
| 1980 | 10 |
| 1981 | 5 |
| 1982 | 37 |
| 1983 | 63 |
| 1984 | 49 |
| 1985 | 29 |
| 1986 | 34 |
| 1987 | 41 |
| 1988 | 34 |
| 1989 | 29 |
| 1990 | 31 |
| 1991 | 48 |
| 1992 | 17 |
| 1993 | 13 |
| 1994 | 5 |
| 1995 | 6 |
| 1997 | 15 |
| 1998 | 19 |
| 1999 | 6 |
| 2000 | 5 |
| 2001 | 5 |
| 2003 | 25 |
| 2004 | 20 |
| 2008 | 19 |
| 2009 | 6 |
| 2010 | 14 |
| 2015 | 14 |
| 2017 | 5 |