| Year | Count |
|---|---|
| 1957 | 741 |
| 1958 | 1,647 |
| 1959 | 2,331 |
| 1960 | 2,720 |
| 1961 | 2,599 |
| 1962 | 3,183 |
| 1963 | 2,513 |
| 1964 | 2,650 |
| 1965 | 2,057 |
| 1966 | 1,738 |
| 1967 | 1,975 |
| 1968 | 2,727 |
| 1969 | 2,539 |
| 1970 | 2,424 |
| 1971 | 2,153 |
| 1972 | 1,640 |
| 1973 | 1,282 |
| 1974 | 1,107 |
| 1975 | 853 |
| 1976 | 757 |
| 1977 | 550 |
| 1978 | 431 |
| 1979 | 402 |
| 1980 | 354 |
| 1981 | 276 |
| 1982 | 240 |
| 1983 | 168 |
| 1984 | 166 |
| 1985 | 140 |
| 1986 | 79 |
| 1987 | 71 |
| 1988 | 33 |
| 1989 | 5 |
| 1990 | 5 |
| 1992 | 17 |