Year mm per year 1961 1604 1962 1604 1963 1604 1964 1604 1965 1604 1966 1604 1967 1604 1968 1604 1969 1604 1970 1604 1971 1604 1972 1604 1973 1604 1974 1604 1975 1604 1976 1604 1977 1604 1978 1604 1979 1604 1980 1604 1981 1604 1982 1604 1983 1604 1984 1604 1985 1604 1986 1604 1987 1604 1988 1604 1989 1604 1990 1604 1991 1604 1992 1604 1993 1604 1994 1604 1995 1604 1996 1604 1997 1604 1998 1604 1999 1604 2000 1604 2001 1604 2002 1604 2003 1604 2004 1604 2005 1604 2006 1604 2007 1604 2008 1604 2009 1604 2010 1604 2011 1604 2012 1604 2013 1604 2014 1604 2015 1604 2016 1604 2017 1604 2018 1604 2019 1604 2020 1604