Year Grams per day 1961 29.64 1962 30.97 1963 33.07 1964 32.44 1965 38.78 1966 44.32 1967 39.38 1968 42.94 1969 36.9 1970 36.3 1971 41.3 1972 34.43 1973 24.37 1974 13.64 1975 8.27 1976 6.26 1977 4.91 1978 5.67 1979 6.6 1980 6.79 1981 5.19 1982 5.48 1983 5.3 1984 4.48 1985 4.58 1986 6.61 1987 11.01 1988 6.28 1989 8.02 1990 8.6 1991 9.87 1992 11.02 1993 10.77 1994 15.38 1995 18.37 1996 17.24 1997 19.61 1998 19.24 1999 19.47 2000 22.66 2001 21.46 2002 22.93 2003 24.09 2004 26.85 2005 25.1 2006 25.85 2007 25.68 2008 26.83 2009 29.35 2010 28.94 2011 25.94 2012 25.29 2013 32.39