| Year | Count |
|---|---|
| 1958 | 5 |
| 1968 | 16 |
| 1969 | 17 |
| 1970 | 12 |
| 1971 | 44 |
| 1972 | 41 |
| 1973 | 36 |
| 1974 | 30 |
| 1975 | 84 |
| 1976 | 72 |
| 1977 | 81 |
| 1978 | 60 |
| 1979 | 114 |
| 1980 | 124 |
| 1981 | 105 |
| 1982 | 64 |
| 1983 | 75 |
| 1984 | 58 |
| 1985 | 81 |
| 1986 | 46 |
| 1987 | 59 |
| 1988 | 29 |
| 1989 | 46 |
| 1990 | 36 |
| 1991 | 58 |
| 1992 | 90 |
| 1993 | 86 |
| 1994 | 85 |
| 1995 | 82 |
| 1996 | 68 |
| 1997 | 65 |
| 1998 | 113 |
| 1999 | 72 |
| 2000 | 79 |
| 2001 | 112 |
| 2002 | 43 |
| 2003 | 35 |
| 2004 | 54 |
| 2005 | 41 |
| 2006 | 54 |
| 2007 | 56 |
| 2008 | 32 |
| 2009 | 44 |
| 2010 | 23 |
| 2011 | 20 |
| 2014 | 26 |
| 2015 | 14 |
| 2016 | 14 |
| 2018 | 27 |
| 2019 | 15 |
| 2021 | 12 |