| Year | Count |
|---|---|
| 1951 | 5 |
| 1955 | 67 |
| 1956 | 58 |
| 1957 | 34 |
| 1958 | 21 |
| 1959 | 45 |
| 1960 | 79 |
| 1961 | 52 |
| 1962 | 111 |
| 1963 | 115 |
| 1964 | 72 |
| 1965 | 53 |
| 1966 | 78 |
| 1967 | 114 |
| 1968 | 98 |
| 1969 | 101 |
| 1970 | 100 |
| 1971 | 155 |
| 1972 | 106 |
| 1973 | 112 |
| 1974 | 109 |
| 1975 | 82 |
| 1976 | 117 |
| 1977 | 63 |
| 1978 | 97 |
| 1979 | 57 |
| 1980 | 56 |
| 1981 | 61 |
| 1982 | 38 |
| 1983 | 62 |
| 1984 | 30 |
| 1985 | 29 |
| 1986 | 46 |
| 1987 | 28 |
| 1988 | 16 |
| 1990 | 25 |
| 1991 | 24 |
| 1992 | 34 |
| 1995 | 6 |
| 1996 | 5 |
| 2000 | 7 |
| 2001 | 10 |
| 2003 | 15 |
| 2005 | 17 |
| 2006 | 6 |
| 2007 | 7 |
| 2008 | 12 |
| 2010 | 10 |
| 2012 | 16 |
| 2014 | 5 |
| 2015 | 5 |
| 2021 | 5 |