| Year | Count |
|---|---|
| 1971 | 5 |
| 1972 | 10 |
| 1973 | 22 |
| 1974 | 5 |
| 1974 | 15 |
| 1975 | 5 |
| 1975 | 40 |
| 1976 | 35 |
| 1977 | 51 |
| 1978 | 44 |
| 1979 | 60 |
| 1980 | 25 |
| 1981 | 26 |
| 1982 | 42 |
| 1983 | 23 |
| 1984 | 20 |
| 1985 | 24 |
| 1986 | 23 |
| 1987 | 34 |
| 1988 | 14 |
| 1989 | 12 |
| 1990 | 8 |
| 1991 | 28 |
| 1992 | 10 |
| 1993 | 17 |
| 1994 | 35 |
| 1995 | 23 |
| 1996 | 6 |
| 1997 | 13 |
| 1998 | 10 |
| 2000 | 8 |
| 2001 | 7 |
| 2003 | 5 |
| 2005 | 5 |
| 2008 | 10 |
| 2009 | 10 |
| 2010 | 5 |
| 2011 | 7 |
| 2013 | 10 |