| Year | Count |
|---|---|
| 1968 | 6 |
| 1969 | 10 |
| 1971 | 5 |
| 1972 | 13 |
| 1973 | 8 |
| 1974 | 16 |
| 1975 | 42 |
| 1976 | 117 |
| 1977 | 147 |
| 1978 | 28 |
| 1979 | 22 |
| 1980 | 51 |
| 1981 | 65 |
| 1982 | 43 |
| 1983 | 27 |
| 1984 | 61 |
| 1985 | 54 |
| 1986 | 66 |
| 1987 | 54 |
| 1988 | 76 |
| 1989 | 68 |
| 1990 | 93 |
| 1991 | 83 |
| 1992 | 46 |
| 1993 | 73 |
| 1994 | 20 |
| 1995 | 27 |
| 1996 | 56 |
| 1997 | 64 |
| 1998 | 76 |
| 1999 | 57 |
| 2000 | 67 |
| 2001 | 45 |
| 2002 | 99 |
| 2003 | 68 |
| 2004 | 106 |
| 2005 | 63 |
| 2006 | 90 |
| 2007 | 67 |
| 2008 | 103 |
| 2009 | 71 |
| 2010 | 111 |
| 2011 | 129 |
| 2012 | 121 |
| 2013 | 93 |
| 2014 | 102 |
| 2015 | 171 |
| 2016 | 172 |
| 2017 | 119 |
| 2018 | 131 |
| 2019 | 69 |
| 2020 | 113 |
| 2021 | 148 |
| 2022 | 141 |
| 2023 | 154 |
| 2024 | 138 |