Year Grams per day 1961 54.6 1962 56.54 1963 55.63 1964 58.13 1965 54.11 1966 51.61 1967 44.02 1968 44.87 1969 40.24 1970 48.23 1971 50.65 1972 54.11 1973 49.94 1974 39.44 1975 46.39 1976 50.87 1977 50.21 1978 40.43 1979 49.04 1980 41.21 1981 46.22 1982 48.8 1983 44.04 1984 46.58 1985 29.59 1986 34.04 1987 31.95 1988 27.84 1989 33.18 1990 44.48 1991 42.2 1992 37.14 1993 37.16 1994 47.89 1995 49.31 1996 48.49 1997 52.59 1998 41.91 1999 39.97 2000 32.18 2001 41.02 2002 35.8 2003 35.91 2004 31.34 2005 32.78 2006 43.92 2007 42.94 2008 37.81 2009 41.95 2010 43.57 2011 43.96 2012 46.13 2013 49.99