| Year | Count |
|---|---|
| 1950 | 6 |
| 1951 | 14 |
| 1952 | 17 |
| 1953 | 29 |
| 1954 | 12 |
| 1955 | 29 |
| 1956 | 69 |
| 1957 | 104 |
| 1958 | 87 |
| 1959 | 178 |
| 1960 | 158 |
| 1961 | 149 |
| 1962 | 118 |
| 1963 | 99 |
| 1964 | 120 |
| 1965 | 75 |
| 1966 | 66 |
| 1967 | 48 |
| 1968 | 42 |
| 1969 | 71 |
| 1970 | 65 |
| 1971 | 46 |
| 1972 | 42 |
| 1973 | 34 |
| 1974 | 34 |
| 1975 | 16 |
| 1976 | 14 |
| 1978 | 15 |
| 1979 | 31 |
| 1980 | 5 |
| 1981 | 7 |
| 1985 | 6 |
| 1989 | 6 |
| 1990 | 35 |
| 1991 | 15 |
| 1992 | 29 |
| 1993 | 10 |
| 1994 | 49 |
| 1995 | 41 |
| 1996 | 24 |
| 1997 | 40 |
| 1998 | 13 |
| 1999 | 25 |
| 2000 | 54 |
| 2001 | 48 |
| 2002 | 41 |
| 2003 | 69 |
| 2004 | 44 |
| 2005 | 58 |
| 2006 | 29 |
| 2007 | 23 |
| 2008 | 13 |
| 2009 | 7 |
| 2010 | 8 |
| 2011 | 9 |
| 2016 | 5 |
| 2018 | 5 |