| Year | Count |
|---|---|
| 1963 | 5 |
| 1969 | 5 |
| 1970 | 6 |
| 1971 | 8 |
| 1972 | 12 |
| 1973 | 18 |
| 1974 | 12 |
| 1975 | 14 |
| 1976 | 22 |
| 1977 | 36 |
| 1978 | 51 |
| 1979 | 58 |
| 1980 | 50 |
| 1981 | 37 |
| 1982 | 30 |
| 1983 | 29 |
| 1984 | 25 |
| 1985 | 33 |
| 1986 | 40 |
| 1987 | 30 |
| 1988 | 29 |
| 1989 | 51 |
| 1990 | 89 |
| 1991 | 62 |
| 1992 | 149 |
| 1993 | 509 |
| 1994 | 2,247 |
| 1995 | 506 |
| 1996 | 292 |
| 1997 | 192 |
| 1998 | 195 |
| 1999 | 100 |
| 2000 | 76 |
| 2001 | 58 |
| 2002 | 46 |
| 2003 | 73 |
| 2004 | 80 |
| 2005 | 59 |
| 2006 | 30 |
| 2007 | 23 |
| 2008 | 28 |
| 2009 | 35 |
| 2010 | 54 |
| 2011 | 73 |
| 2012 | 66 |
| 2013 | 102 |
| 2014 | 75 |
| 2015 | 125 |
| 2016 | 138 |
| 2017 | 146 |
| 2018 | 95 |
| 2019 | 124 |
| 2020 | 117 |
| 2021 | 118 |
| 2022 | 138 |
| 2023 | 160 |
| 2024 | 185 |