Year	mm per year
1961	1343
1962	1343
1963	1343
1964	1343
1965	1343
1966	1343
1967	1343
1968	1343
1969	1343
1970	1343
1971	1343
1972	1343
1973	1343
1974	1343
1975	1343
1976	1343
1977	1343
1978	1343
1979	1343
1980	1343
1981	1343
1982	1343
1983	1343
1984	1343
1985	1343
1986	1343
1987	1343
1988	1343
1989	1343
1990	1343
1991	1343
1992	1343
1993	1343
1994	1343
1995	1343
1996	1343
1997	1343
1998	1343
1999	1343
2000	1343
2001	1343
2002	1343
2003	1343
2004	1343
2005	1343
2006	1343
2007	1343
2008	1343
2009	1343
2010	1343
2011	1343
2012	1343
2013	1343
2014	1343
2015	1343
2016	1343
2017	1343
2018	1343
2019	1343
2020	1343