| Year | Count |
|---|---|
| 1967 | 5 |
| 1968 | 6 |
| 1970 | 5 |
| 1971 | 5 |
| 1973 | 15 |
| 1974 | 5 |
| 1975 | 15 |
| 1976 | 16 |
| 1977 | 21 |
| 1978 | 11 |
| 1979 | 17 |
| 1980 | 5 |
| 1981 | 7 |
| 1982 | 5 |
| 1984 | 5 |
| 1985 | 6 |
| 1986 | 12 |
| 1988 | 7 |
| 1989 | 20 |
| 1990 | 33 |
| 1991 | 12 |
| 1992 | 8 |
| 1993 | 29 |
| 1994 | 120 |
| 1995 | 278 |
| 1996 | 200 |
| 1997 | 123 |
| 1998 | 125 |
| 1999 | 111 |
| 2000 | 101 |
| 2001 | 157 |
| 2002 | 86 |
| 2003 | 105 |
| 2004 | 81 |
| 2005 | 85 |
| 2006 | 88 |
| 2007 | 66 |
| 2008 | 87 |
| 2009 | 45 |
| 2010 | 47 |
| 2011 | 51 |
| 2012 | 48 |
| 2013 | 47 |
| 2014 | 42 |
| 2015 | 20 |
| 2016 | 75 |
| 2017 | 39 |
| 2018 | 24 |
| 2019 | 44 |
| 2020 | 97 |
| 2021 | 58 |
| 2022 | 35 |
| 2023 | 37 |
| 2024 | 40 |