Year	years
1970	5
1971	5
1972	5
1973	5
1974	5
1975	5
1976	5
1977	5
1978	5
1979	5
1980	5
1981	5
1982	5
1983	5
1984	5
1985	5
1986	5
1987	5
1988	5
1989	5
1990	5
1991	5
1992	5
1993	5
1994	5
1995	5
1996	5
1997	7
1998	7
1999	7
2000	7
2001	7
2002	7
2003	7
2004	7
2005	7
2006	7
2007	7
2008	7
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