| 1960s | 1965: 2, 1966: 3, 1967: 5, 1968: 5, 1969: 12 |
| 1970s | 1970: 20, 1971: 13, 1972: 9, 1973: 13, 1974: 11, 1975: 12, 1976: 6, 1977: 8, 1978: 12, 1979: 9 |
| 1980s | 1980: 8, 1981: 6, 1982: 9, 1983: 14, 1984: 12, 1985: 10, 1986: 13, 1987: 13, 1988: 18, 1989: 19 |
| 1990s | 1990: 19, 1991: 35, 1992: 32, 1993: 41, 1994: 30, 1995: 52, 1996: 58, 1997: 52, 1998: 50, 1999: 50 |
| 2000s | 2000: 48, 2001: 43, 2002: 54, 2003: 46, 2004: 52, 2005: 41, 2006: 42, 2007: 43, 2008: 40, 2009: 40 |
| 2010s | 2010: 38, 2011: 38, 2012: 37, 2013: 33, 2014: 36, 2015: 27, 2016: 33, 2017: 26, 2018: 22, 2019: 29 |
| 2020s | 2020: 21, 2021: 21, 2022: 15, 2023: 19, 2024: 13 |
