| Year | Count |
|---|---|
| 1968 | 6 |
| 1970 | 6 |
| 1971 | 6 |
| 1972 | 5 |
| 1973 | 5 |
| 1974 | 9 |
| 1975 | 6 |
| 1976 | 8 |
| 1977 | 20 |
| 1978 | 19 |
| 1979 | 18 |
| 1980 | 42 |
| 1981 | 17 |
| 1982 | 22 |
| 1983 | 19 |
| 1984 | 14 |
| 1985 | 10 |
| 1986 | 22 |
| 1987 | 20 |
| 1988 | 32 |
| 1989 | 38 |
| 1990 | 60 |
| 1991 | 71 |
| 1992 | 132 |
| 1993 | 48 |
| 1994 | 125 |
| 1995 | 96 |
| 1996 | 94 |
| 1997 | 138 |
| 1998 | 127 |
| 1999 | 102 |
| 2000 | 99 |
| 2001 | 134 |
| 2002 | 119 |
| 2003 | 124 |
| 2004 | 217 |
| 2005 | 287 |
| 2006 | 216 |
| 2007 | 215 |
| 2008 | 178 |
| 2009 | 69 |
| 2010 | 118 |
| 2011 | 105 |
| 2012 | 370 |
| 2013 | 150 |
| 2014 | 157 |
| 2015 | 270 |
| 2016 | 332 |
| 2017 | 386 |
| 2018 | 239 |
| 2019 | 216 |
| 2020 | 177 |
| 2021 | 155 |
| 2022 | 246 |
| 2023 | 209 |
| 2024 | 230 |