| Year | Count |
|---|---|
| 1975 | 34 |
| 1976 | 959 |
| 1977 | 1,933 |
| 1978 | 384 |
| 1979 | 200 |
| 1980 | 144 |
| 1981 | 87 |
| 1982 | 89 |
| 1983 | 48 |
| 1984 | 67 |
| 1985 | 66 |
| 1986 | 100 |
| 1987 | 159 |
| 1988 | 158 |
| 1989 | 74 |
| 1990 | 86 |
| 1991 | 70 |
| 1992 | 77 |
| 1993 | 81 |
| 1994 | 70 |
| 1995 | 90 |
| 1996 | 76 |
| 1997 | 111 |
| 1998 | 101 |
| 1999 | 36 |
| 2000 | 68 |
| 2001 | 108 |
| 2002 | 69 |
| 2003 | 54 |
| 2004 | 97 |
| 2005 | 94 |
| 2006 | 158 |
| 2007 | 142 |
| 2008 | 161 |
| 2009 | 173 |
| 2010 | 516 |
| 2011 | 588 |
| 2012 | 590 |
| 2013 | 487 |
| 2014 | 293 |
| 2015 | 409 |
| 2016 | 272 |
| 2017 | 282 |
| 2018 | 213 |
| 2019 | 163 |
| 2020 | 189 |
| 2021 | 145 |
| 2022 | 142 |
| 2023 | 108 |
| 2024 | 167 |