Year mm per year 1961 2666 1962 2666 1963 2666 1964 2666 1965 2666 1966 2666 1967 2666 1968 2666 1969 2666 1970 2666 1971 2666 1972 2666 1973 2666 1974 2666 1975 2666 1976 2666 1977 2666 1978 2666 1979 2666 1980 2666 1981 2666 1982 2666 1983 2666 1984 2666 1985 2666 1986 2666 1987 2666 1988 2666 1989 2666 1990 2666 1991 2666 1992 2666 1993 2666 1994 2666 1995 2666 1996 2666 1997 2666 1998 2666 1999 2666 2000 2666 2001 2666 2002 2666 2003 2666 2004 2666 2005 2666 2006 2666 2007 2666 2008 2666 2009 2666 2010 2666 2011 2666 2012 2666 2013 2666 2014 2666 2015 2666 2016 2666 2017 2666 2018 2666 2019 2666 2020 2666