Year	mm per year
1961	2330
1962	2330
1963	2330
1964	2330
1965	2330
1966	2330
1967	2330
1968	2330
1969	2330
1970	2330
1971	2330
1972	2330
1973	2330
1974	2330
1975	2330
1976	2330
1977	2330
1978	2330
1979	2330
1980	2330
1981	2330
1982	2330
1983	2330
1984	2330
1985	2330
1986	2330
1987	2330
1988	2330
1989	2330
1990	2330
1991	2330
1992	2330
1993	2330
1994	2330
1995	2330
1996	2330
1997	2330
1998	2330
1999	2330
2000	1970
2001	2330
2002	2330
2003	2330
2004	2330
2005	2330
2006	2330
2007	2330
2008	2330
2009	2330
2010	2330
2011	2330
2012	2330
2013	2330
2014	2330
2015	2330
2016	2330
2017	2330
2018	2330
2019	2330
2020	2330