Year Grams per day 1961 2.69 1962 2.79 1963 2.94 1964 3.09 1965 3.4 1966 3.71 1967 2.64 1968 3.02 1969 4 1970 4.37 1971 3.38 1972 3.43 1973 5.56 1974 4.12 1975 4.64 1976 3.48 1977 4.77 1978 6.97 1979 5.84 1980 2.11 1981 6.92 1982 5.73 1983 4.71 1984 6.03 1985 8.42 1986 12.08 1987 8.09 1988 9.98 1989 8.51 1990 9.88 1991 10.7 1992 11.22 1993 12.93 1994 7.09 1995 9.73 1996 10.83 1997 13.6 1998 12.17 1999 13.5 2000 14.24 2001 13.61 2002 13.26 2003 13.67 2004 13.8 2005 12.9 2006 13.81 2007 13.93 2008 12.72 2009 12.52 2010 11.78 2011 11.92 2012 12.54 2013 12.98