Year	mm per year
1961	1604
1962	1604
1963	1604
1964	1604
1965	1604
1966	1604
1967	1604
1968	1604
1969	1604
1970	1604
1971	1604
1972	1604
1973	1604
1974	1604
1975	1604
1976	1604
1977	1604
1978	1604
1979	1604
1980	1604
1981	1604
1982	1604
1983	1604
1984	1604
1985	1604
1986	1604
1987	1604
1988	1604
1989	1604
1990	1604
1991	1604
1992	1604
1993	1604
1994	1604
1995	1604
1996	1604
1997	1604
1998	1604
1999	1604
2000	1604
2001	1604
2002	1604
2003	1604
2004	1604
2005	1604
2006	1604
2007	1604
2008	1604
2009	1604
2010	1604
2011	1604
2012	1604
2013	1604
2014	1604
2015	1604
2016	1604
2017	1604
2018	1604
2019	1604
2020	1604