| Year | Count |
|---|---|
| 1966 | 5 |
| 1968 | 19 |
| 1969 | 19 |
| 1970 | 14 |
| 1971 | 18 |
| 1972 | 28 |
| 1973 | 20 |
| 1974 | 20 |
| 1975 | 14 |
| 1976 | 28 |
| 1977 | 58 |
| 1978 | 74 |
| 1979 | 56 |
| 1980 | 70 |
| 1981 | 34 |
| 1982 | 28 |
| 1983 | 43 |
| 1984 | 40 |
| 1985 | 59 |
| 1986 | 49 |
| 1987 | 84 |
| 1988 | 54 |
| 1989 | 58 |
| 1990 | 79 |
| 1991 | 73 |
| 1992 | 61 |
| 1993 | 50 |
| 1994 | 51 |
| 1995 | 49 |
| 1996 | 52 |
| 1997 | 36 |
| 1998 | 37 |
| 1999 | 33 |
| 2000 | 15 |
| 2001 | 23 |
| 2002 | 16 |
| 2003 | 13 |
| 2005 | 10 |
| 2006 | 11 |
| 2008 | 8 |
| 2009 | 8 |
| 2011 | 8 |
| 2014 | 5 |