Year Grams per day 1961 123.72 1962 113.69 1963 89.33 1964 117.6 1965 119.68 1966 128.1 1967 124.61 1968 127.27 1969 136.15 1970 139.53 1971 135.97 1972 136.77 1973 139.99 1974 133.03 1975 122.59 1976 121.81 1977 113.29 1978 104.59 1979 91.46 1980 104.77 1981 99.86 1982 100.01 1983 101.68 1984 96.79 1985 101.23 1986 93.08 1987 97.05 1988 105.68 1989 112.33 1990 115.85 1991 111.21 1992 118.9 1993 120.46 1994 110.4 1995 109.62 1996 104.02 1997 105.29 1998 100.65 1999 100.42 2000 105.35 2001 95.78 2002 95.28 2003 94.06 2004 95.43 2005 93.23 2006 91.4 2007 94.38 2008 81.94 2009 92.66 2010 84.36 2011 85.82 2012 86.84 2013 86.78