Year	mm per year
1961	2091
1962	2091
1963	2091
1964	2091
1965	2091
1966	2091
1967	2091
1968	2091
1969	2091
1970	2091
1971	2091
1972	2091
1973	2091
1974	2091
1975	2091
1976	2091
1977	2091
1978	2091
1979	2091
1980	2091
1981	2091
1982	2091
1983	2091
1984	2091
1985	2091
1986	2091
1987	2091
1988	2091
1989	2091
1990	2091
1991	2091
1992	2091
1993	2091
1994	2091
1995	2091
1996	2091
1997	2091
1998	2091
1999	2091
2000	2091
2001	2091
2002	2091
2003	2091
2004	2091
2005	2091
2006	2091
2007	2091
2008	2091
2009	2091
2010	2091
2011	2091
2012	2091
2013	2091
2014	2091
2015	2091
2016	2091
2017	2091
2018	2091
2019	2091
2020	2091