| Year | Count |
|---|---|
| 1945 | 5 |
| 1946 | 5 |
| 1947 | 21 |
| 1948 | 57 |
| 1949 | 51 |
| 1950 | 30 |
| 1951 | 23 |
| 1952 | 8 |
| 1953 | 24 |
| 1954 | 18 |
| 1955 | 30 |
| 1956 | 88 |
| 1957 | 42 |
| 1958 | 36 |
| 1959 | 7 |
| 1960 | 5 |
| 1961 | 18 |
| 1962 | 5 |
| 1964 | 12 |
| 1968 | 6 |
| 1970 | 5 |
| 1973 | 6 |
| 1975 | 10 |
| 1977 | 15 |
| 1978 | 20 |
| 1979 | 68 |
| 1980 | 117 |
| 1981 | 218 |
| 1982 | 215 |
| 1983 | 193 |
| 1984 | 219 |
| 1985 | 257 |
| 1986 | 185 |
| 1987 | 208 |
| 1988 | 163 |
| 1989 | 150 |
| 1990 | 70 |
| 1991 | 82 |
| 1992 | 30 |
| 1993 | 42 |
| 1997 | 10 |