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