Year Grams per day 1961 22.76 1962 23.13 1963 20.92 1964 20.03 1965 23.89 1966 25.67 1967 25.42 1968 24.85 1969 27.72 1970 27.1 1971 28.33 1972 27.26 1973 25.15 1974 19.38 1975 18.38 1976 20.17 1977 19.44 1978 19.69 1979 22.11 1980 19.13 1981 18.36 1982 20.05 1983 16.11 1984 14.83 1985 15.8 1986 13.52 1987 14.22 1988 15.38 1989 13.57 1990 13.38 1991 14.12 1992 14.35 1993 14.5 1994 14.07 1995 12.19 1996 10.44 1997 9.5 1998 14.68 1999 14.14 2000 14.14 2001 13.53 2002 13.77 2003 15.66 2004 14.95 2005 14.64 2006 18.46 2007 18.35 2008 18.28 2009 18.26 2010 10.39 2011 15.59 2012 14.6 2013 16.5