| Year | Count |
|---|---|
| 1952 | 8 |
| 1953 | 22 |
| 1954 | 6 |
| 1955 | 13 |
| 1956 | 25 |
| 1957 | 32 |
| 1958 | 58 |
| 1959 | 95 |
| 1960 | 92 |
| 1961 | 168 |
| 1962 | 237 |
| 1963 | 221 |
| 1964 | 322 |
| 1965 | 380 |
| 1966 | 468 |
| 1967 | 618 |
| 1968 | 577 |
| 1969 | 560 |
| 1970 | 565 |
| 1971 | 484 |
| 1972 | 433 |
| 1973 | 380 |
| 1974 | 233 |
| 1975 | 163 |
| 1976 | 113 |
| 1977 | 49 |
| 1978 | 18 |
| 1979 | 51 |
| 1980 | 29 |
| 1981 | 14 |
| 1982 | 7 |
| 1983 | 12 |
| 1987 | 12 |