Year Grams per day 1961 12.86 1962 14.16 1963 16.21 1964 16.81 1965 14.6 1966 17.49 1967 16.76 1968 14.26 1969 12.61 1970 11.71 1971 12.59 1972 12.85 1973 16.37 1974 13.65 1975 9.35 1976 11.9 1977 11.95 1978 12.57 1979 12.91 1980 9.76 1981 14.2 1982 14.74 1983 15.75 1984 17.45 1985 18.66 1986 19.81 1987 19.51 1988 19.44 1989 18.97 1990 21.22 1991 21.42 1992 20.38 1993 19.89 1994 19.22 1995 19.13 1996 23.85 1997 28.6 1998 27.64 1999 29.92 2000 30.56 2001 35.95 2002 34.82 2003 36.85 2004 37.55 2005 36.97 2006 38.77 2007 46.82 2008 47.9 2009 46.95 2010 45.3 2011 46.75 2012 47.58 2013 46.22