| Year | Count |
|---|---|
| 1970 | 8 |
| 1973 | 6 |
| 1974 | 15 |
| 1975 | 19 |
| 1976 | 52 |
| 1977 | 66 |
| 1978 | 43 |
| 1979 | 62 |
| 1980 | 63 |
| 1981 | 58 |
| 1982 | 33 |
| 1983 | 54 |
| 1984 | 48 |
| 1985 | 70 |
| 1986 | 75 |
| 1987 | 82 |
| 1988 | 93 |
| 1989 | 57 |
| 1990 | 83 |
| 1991 | 65 |
| 1992 | 215 |
| 1993 | 171 |
| 1994 | 175 |
| 1995 | 125 |
| 1996 | 191 |
| 1997 | 333 |
| 1998 | 333 |
| 1999 | 220 |
| 2000 | 144 |
| 2001 | 216 |
| 2002 | 203 |
| 2003 | 224 |
| 2004 | 495 |
| 2005 | 438 |
| 2006 | 266 |
| 2007 | 335 |
| 2008 | 211 |
| 2009 | 182 |
| 2010 | 101 |
| 2011 | 144 |
| 2012 | 136 |
| 2013 | 80 |
| 2014 | 25 |
| 2015 | 91 |
| 2016 | 75 |
| 2017 | 72 |
| 2018 | 45 |
| 2019 | 66 |
| 2020 | 74 |
| 2021 | 69 |
| 2022 | 138 |
| 2023 | 91 |
| 2024 | 129 |