Year Grams per day 1961 26.71 1962 28.95 1963 29.04 1964 31.14 1965 34.32 1966 42.06 1967 43.75 1968 40.68 1969 42.5 1970 37.77 1971 35.6 1972 28.31 1973 28.38 1974 29.21 1975 27.67 1976 27.79 1977 25.83 1978 23.96 1979 24.88 1980 24.26 1981 24.28 1982 24.11 1983 23.74 1984 23.33 1985 21.29 1986 24.2 1987 23.67 1988 23.95 1989 23.3 1990 22.37 1991 20.16 1992 20.07 1993 20.83 1994 20 1995 19.39 1996 18.92 1997 22.58 1998 20.74 1999 18.61 2000 18.14 2001 22.27 2002 18.51 2003 17.1 2004 21.91 2005 28.7 2006 24.64 2007 23.68 2008 22.68 2009 22.84 2010 21.92 2011 22.55 2012 22.28 2013 22.09