| Year | Count |
|---|---|
| 1953 | 10 |
| 1955 | 5 |
| 1957 | 15 |
| 1965 | 5 |
| 1969 | 15 |
| 1970 | 26 |
| 1971 | 16 |
| 1972 | 12 |
| 1973 | 16 |
| 1974 | 29 |
| 1975 | 66 |
| 1976 | 29 |
| 1977 | 17 |
| 1978 | 112 |
| 1979 | 67 |
| 1980 | 180 |
| 1981 | 204 |
| 1982 | 236 |
| 1983 | 264 |
| 1984 | 262 |
| 1985 | 345 |
| 1986 | 282 |
| 1987 | 279 |
| 1988 | 297 |
| 1989 | 279 |
| 1990 | 284 |
| 1991 | 193 |
| 1992 | 180 |
| 1993 | 175 |
| 1994 | 114 |
| 1995 | 39 |
| 1996 | 35 |
| 1997 | 58 |
| 1998 | 26 |
| 1999 | 13 |
| 2000 | 21 |
| 2001 | 5 |
| 2002 | 10 |
| 2004 | 36 |
| 2005 | 22 |
| 2007 | 26 |
| 2008 | 20 |
| 2010 | 11 |
| 2012 | 14 |
| 2014 | 5 |
| 2016 | 5 |