Year	years
1970	8
1971	8
1972	8
1973	8
1974	8
1975	8
1976	8
1977	8
1978	8
1979	8
1980	8
1981	8
1982	8
1983	8
1984	8
1985	8
1986	8
1987	8
1988	8
1989	8
1990	8
1991	8
1992	8
1993	8
1994	8
1995	8
1996	8
1997	8
1998	8
1999	8
2000	8
2001	8
2002	8
2003	8
2004	8
2005	8
2006	8
2007	8
2008	8
2009	7
2010	7
2011	7
2012	7
2013	7
2014	7
2015	7
2016	7
2017	7
2018	7
2019	7
2020	7
2021	7
2022	7
2023	7