| Year | Count |
|---|---|
| 1971 | 7 |
| 1974 | 5 |
| 1977 | 18 |
| 1978 | 5 |
| 1979 | 19 |
| 1981 | 10 |
| 1982 | 27 |
| 1983 | 15 |
| 1984 | 21 |
| 1985 | 36 |
| 1986 | 56 |
| 1987 | 60 |
| 1988 | 34 |
| 1989 | 27 |
| 1990 | 61 |
| 1991 | 123 |
| 1992 | 93 |
| 1993 | 127 |
| 1994 | 149 |
| 1995 | 123 |
| 1996 | 142 |
| 1997 | 257 |
| 1998 | 236 |
| 1999 | 266 |
| 2000 | 298 |
| 2001 | 327 |
| 2002 | 300 |
| 2003 | 328 |
| 2004 | 374 |
| 2005 | 421 |
| 2006 | 367 |
| 2007 | 319 |
| 2008 | 344 |
| 2009 | 264 |
| 2010 | 219 |
| 2011 | 253 |
| 2012 | 239 |
| 2013 | 291 |
| 2014 | 250 |
| 2015 | 223 |
| 2016 | 312 |
| 2017 | 438 |
| 2018 | 287 |
| 2019 | 295 |
| 2020 | 314 |
| 2021 | 329 |
| 2022 | 401 |
| 2023 | 399 |
| 2024 | 394 |