| Year | Count |
|---|---|
| 1969 | 5 |
| 1970 | 5 |
| 1973 | 6 |
| 1974 | 5 |
| 1975 | 14 |
| 1976 | 15 |
| 1978 | 23 |
| 1979 | 17 |
| 1980 | 9 |
| 1981 | 13 |
| 1982 | 24 |
| 1983 | 14 |
| 1984 | 13 |
| 1985 | 42 |
| 1986 | 45 |
| 1987 | 25 |
| 1988 | 17 |
| 1989 | 5 |
| 1990 | 19 |
| 1991 | 6 |
| 1992 | 19 |
| 1993 | 15 |
| 1994 | 14 |
| 1995 | 23 |
| 1996 | 26 |
| 1997 | 40 |
| 1998 | 102 |
| 1999 | 51 |
| 2000 | 111 |
| 2001 | 187 |
| 2002 | 167 |
| 2003 | 225 |
| 2004 | 458 |
| 2005 | 578 |
| 2006 | 767 |
| 2007 | 878 |
| 2008 | 852 |
| 2009 | 833 |
| 2010 | 863 |
| 2011 | 1,130 |
| 2012 | 1,400 |
| 2013 | 1,308 |
| 2014 | 1,246 |
| 2015 | 1,318 |
| 2016 | 1,362 |
| 2017 | 1,374 |
| 2018 | 1,113 |
| 2019 | 1,122 |
| 2020 | 953 |
| 2021 | 925 |
| 2022 | 1,010 |
| 2023 | 957 |
| 2024 | 878 |