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