| Year | Count |
|---|---|
| 1953 | 10 |
| 1955 | 38 |
| 1956 | 30 |
| 1957 | 55 |
| 1958 | 62 |
| 1959 | 108 |
| 1960 | 164 |
| 1961 | 201 |
| 1962 | 183 |
| 1963 | 147 |
| 1964 | 199 |
| 1965 | 231 |
| 1966 | 262 |
| 1967 | 331 |
| 1968 | 305 |
| 1969 | 301 |
| 1970 | 318 |
| 1971 | 231 |
| 1972 | 173 |
| 1973 | 118 |
| 1974 | 49 |
| 1975 | 65 |
| 1976 | 41 |
| 1977 | 48 |
| 1978 | 29 |
| 1979 | 43 |
| 1980 | 133 |
| 1981 | 85 |
| 1982 | 13 |
| 1983 | 19 |
| 1984 | 24 |
| 1985 | 21 |
| 1986 | 41 |
| 1987 | 15 |
| 1988 | 20 |