Year	years
1970	10
1971	10
1972	10
1973	10
1974	10
1975	10
1976	10
1977	10
1978	10
1979	10
1980	10
1981	10
1982	10
1983	10
1984	10
1985	10
1986	10
1987	10
1988	10
1989	10
1990	10
1991	10
1992	10
1993	10
1994	10
1995	10
1996	10
1997	10
1998	10
1999	10
2000	10
2001	10
2002	10
2003	10
2004	10
2005	10
2006	10
2007	12
2008	12
2009	12
2010	12
2011	12
2012	12
2013	12
2014	12
2015	12
2016	12
2017	12
2018	12
2019	12
2020	12
2021	12
2022	12
2023	12