| Year | Count |
|---|---|
| 1955 | 10 |
| 1964 | 20 |
| 1965 | 10 |
| 1971 | 10 |
| 1972 | 12 |
| 1975 | 15 |
| 1976 | 44 |
| 1977 | 6 |
| 1978 | 43 |
| 1979 | 53 |
| 1980 | 49 |
| 1981 | 62 |
| 1982 | 98 |
| 1983 | 130 |
| 1984 | 167 |
| 1985 | 328 |
| 1986 | 265 |
| 1987 | 329 |
| 1988 | 373 |
| 1989 | 565 |
| 1990 | 585 |
| 1991 | 609 |
| 1992 | 986 |
| 1993 | 1,065 |
| 1994 | 1,077 |
| 1995 | 943 |
| 1996 | 958 |
| 1997 | 861 |
| 1998 | 878 |
| 1999 | 853 |
| 2000 | 829 |
| 2001 | 715 |
| 2002 | 634 |
| 2003 | 645 |
| 2004 | 592 |
| 2005 | 588 |
| 2006 | 488 |
| 2007 | 394 |
| 2008 | 401 |
| 2009 | 341 |
| 2010 | 337 |
| 2011 | 183 |
| 2012 | 153 |
| 2013 | 116 |
| 2014 | 112 |
| 2015 | 87 |
| 2016 | 45 |
| 2017 | 68 |
| 2018 | 40 |
| 2019 | 22 |
| 2020 | 6 |
| 2021 | 6 |
| 2022 | 5 |
| 2023 | 16 |