Year mm per year 1961 2091 1962 2091 1963 2091 1964 2091 1965 2091 1966 2091 1967 2091 1968 2091 1969 2091 1970 2091 1971 2091 1972 2091 1973 2091 1974 2091 1975 2091 1976 2091 1977 2091 1978 2091 1979 2091 1980 2091 1981 2091 1982 2091 1983 2091 1984 2091 1985 2091 1986 2091 1987 2091 1988 2091 1989 2091 1990 2091 1991 2091 1992 2091 1993 2091 1994 2091 1995 2091 1996 2091 1997 2091 1998 2091 1999 2091 2000 2091 2001 2091 2002 2091 2003 2091 2004 2091 2005 2091 2006 2091 2007 2091 2008 2091 2009 2091 2010 2091 2011 2091 2012 2091 2013 2091 2014 2091 2015 2091 2016 2091 2017 2091 2018 2091 2019 2091 2020 2091