| Year | Count |
|---|---|
| 1974 | 5 |
| 1976 | 12 |
| 1977 | 19 |
| 1978 | 17 |
| 1979 | 27 |
| 1980 | 12 |
| 1981 | 13 |
| 1983 | 16 |
| 1984 | 25 |
| 1985 | 33 |
| 1986 | 15 |
| 1987 | 29 |
| 1988 | 35 |
| 1989 | 255 |
| 1990 | 267 |
| 1991 | 242 |
| 1992 | 247 |
| 1993 | 144 |
| 1994 | 285 |
| 1995 | 262 |
| 1996 | 236 |
| 1997 | 254 |
| 1998 | 163 |
| 1999 | 106 |
| 2000 | 111 |
| 2001 | 110 |
| 2002 | 71 |
| 2003 | 45 |
| 2004 | 51 |
| 2005 | 51 |
| 2006 | 58 |
| 2007 | 35 |
| 2008 | 14 |
| 2009 | 53 |
| 2010 | 56 |
| 2011 | 64 |
| 2012 | 47 |
| 2013 | 65 |
| 2014 | 38 |
| 2015 | 169 |
| 2016 | 280 |
| 2017 | 254 |
| 2018 | 176 |
| 2019 | 180 |
| 2020 | 221 |
| 2021 | 155 |
| 2022 | 185 |
| 2023 | 159 |
| 2024 | 119 |