| Year | Count |
|---|---|
| 1975 | 18 |
| 1977 | 7 |
| 1978 | 147 |
| 1979 | 86 |
| 1980 | 141 |
| 1981 | 89 |
| 1982 | 158 |
| 1983 | 183 |
| 1984 | 153 |
| 1985 | 340 |
| 1986 | 214 |
| 1987 | 296 |
| 1988 | 301 |
| 1989 | 473 |
| 1990 | 384 |
| 1991 | 483 |
| 1992 | 410 |
| 1993 | 466 |
| 1994 | 451 |
| 1995 | 348 |
| 1996 | 436 |
| 1997 | 380 |
| 1998 | 351 |
| 1999 | 225 |
| 2000 | 300 |
| 2001 | 310 |
| 2002 | 265 |
| 2003 | 253 |
| 2004 | 332 |
| 2005 | 338 |
| 2006 | 297 |
| 2007 | 267 |
| 2008 | 220 |
| 2009 | 183 |
| 2010 | 194 |
| 2011 | 191 |
| 2012 | 88 |
| 2013 | 69 |
| 2014 | 41 |
| 2015 | 75 |
| 2016 | 44 |
| 2017 | 20 |
| 2018 | 24 |
| 2019 | 28 |
| 2020 | 16 |
| 2021 | 17 |
| 2022 | 17 |
| 2023 | 17 |
| 2024 | 10 |