Year mm per year 1961 2702 1962 2702 1963 2702 1964 2702 1965 2702 1966 2702 1967 2702 1968 2702 1969 2702 1970 2702 1971 2702 1972 2702 1973 2702 1974 2702 1975 2702 1976 2702 1977 2702 1978 2702 1979 2702 1980 2702 1981 2702 1982 2702 1983 2702 1984 2702 1985 2702 1986 2702 1987 2702 1988 2702 1989 2702 1990 2702 1991 2702 1992 2702 1993 2702 1994 2702 1995 2702 1996 2702 1997 2702 1998 2702 1999 2702 2000 2702 2001 2702 2002 2702 2003 2702 2004 2702 2005 2702 2006 2702 2007 2702 2008 2702 2009 2702 2010 2702 2011 2702 2012 2702 2013 2702 2014 2702 2015 2702 2016 2702 2017 2702 2018 2702 2019 2702 2020 2702