Year	years
1970	13
1971	13
1972	13
1973	13
1974	13
1975	13
1976	13
1977	13
1978	13
1979	13
1980	12
1981	12
1982	12
1983	12
1984	12
1985	12
1986	12
1987	12
1988	12
1989	12
1990	12
1991	12
1992	12
1993	12
1994	12
1995	12
1996	12
1997	12
1998	12
1999	12
2000	12
2001	12
2002	12
2003	12
2004	12
2005	12
2006	12
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