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