Year Grams per day 1961 14.38 1962 12.78 1963 13.21 1964 15.48 1965 16.27 1966 16.74 1967 17.41 1968 17.8 1969 14.48 1970 18.81 1971 15.85 1972 14.83 1973 14.45 1974 14.79 1975 14.91 1976 15.72 1977 16.5 1978 17.35 1979 19.39 1980 20.21 1981 16.69 1982 20.17 1983 25.07 1984 23.81 1985 19.72 1986 20.31 1987 20.62 1988 20.75 1989 14.3 1990 10 1991 9.61 1992 10.75 1993 9.12 1994 8.22 1995 8.45 1996 7.24 1997 7.85 1998 8.34 1999 8.9 2000 8.74 2001 8.4 2002 9.46 2003 12.2 2004 15.5 2005 18.63 2006 19.7 2007 20.82 2008 23.36 2009 23.28 2010 24.25 2011 24.8 2012 25.36 2013 24.53