| Year | Count |
|---|---|
| 1961 | 5 |
| 1967 | 5 |
| 1970 | 6 |
| 1971 | 7 |
| 1972 | 5 |
| 1975 | 9 |
| 1976 | 6 |
| 1977 | 10 |
| 1978 | 5 |
| 1979 | 5 |
| 1980 | 20 |
| 1981 | 13 |
| 1982 | 7 |
| 1983 | 13 |
| 1984 | 20 |
| 1985 | 41 |
| 1986 | 20 |
| 1987 | 31 |
| 1988 | 43 |
| 1989 | 58 |
| 1990 | 61 |
| 1991 | 53 |
| 1992 | 47 |
| 1993 | 88 |
| 1994 | 103 |
| 1995 | 80 |
| 1996 | 58 |
| 1997 | 54 |
| 1998 | 104 |
| 1999 | 101 |
| 2000 | 96 |
| 2001 | 51 |
| 2002 | 113 |
| 2003 | 101 |
| 2004 | 82 |
| 2005 | 117 |
| 2006 | 118 |
| 2007 | 105 |
| 2008 | 102 |
| 2009 | 80 |
| 2010 | 80 |
| 2011 | 76 |
| 2012 | 71 |
| 2013 | 65 |
| 2014 | 79 |
| 2015 | 64 |
| 2016 | 64 |
| 2017 | 64 |
| 2018 | 45 |
| 2019 | 28 |
| 2020 | 53 |
| 2021 | 29 |
| 2022 | 6 |
| 2023 | 28 |
| 2024 | 20 |