| Year | Count |
|---|---|
| 1971 | 13 |
| 1973 | 6 |
| 1975 | 22 |
| 1976 | 35 |
| 1977 | 154 |
| 1978 | 105 |
| 1979 | 84 |
| 1980 | 37 |
| 1981 | 34 |
| 1982 | 34 |
| 1983 | 31 |
| 1984 | 25 |
| 1985 | 16 |
| 1986 | 8 |
| 1987 | 17 |
| 1988 | 19 |
| 1989 | 11 |
| 1990 | 45 |
| 1991 | 25 |
| 1992 | 24 |
| 1993 | 16 |
| 1994 | 25 |
| 1995 | 9 |
| 1997 | 7 |
| 1998 | 17 |
| 2001 | 12 |
| 2003 | 30 |
| 2004 | 23 |
| 2005 | 68 |
| 2006 | 65 |
| 2007 | 75 |
| 2008 | 152 |
| 2009 | 66 |
| 2010 | 112 |
| 2011 | 134 |
| 2012 | 142 |
| 2013 | 127 |
| 2014 | 98 |
| 2015 | 153 |
| 2016 | 169 |
| 2017 | 217 |
| 2018 | 251 |
| 2019 | 237 |
| 2020 | 250 |
| 2021 | 182 |
| 2022 | 198 |
| 2023 | 136 |
| 2024 | 94 |