Year	mm per year
1961	92
1962	92
1963	92
1964	92
1965	92
1966	92
1967	92
1968	92
1969	92
1970	92
1971	92
1972	92
1973	92
1974	92
1975	92
1976	92
1977	92
1978	92
1979	92
1980	92
1981	92
1982	92
1983	92
1984	92
1985	92
1986	92
1987	92
1988	92
1989	92
1990	92
1991	92
1992	92
1993	92
1994	92
1995	92
1996	92
1997	92
1998	92
1999	92
2000	92
2001	92
2002	92
2003	92
2004	92
2005	92
2006	92
2007	92
2008	92
2009	92
2010	92
2011	92
2012	92
2013	92
2014	92
2015	92
2016	92
2017	92
2018	92
2019	92
2020	92