Year Grams per day 1961 36.76 1962 44.54 1963 34.79 1964 33.47 1965 40.02 1966 37.32 1967 44.86 1968 43.86 1969 47.67 1970 48.32 1971 53.43 1972 46.65 1973 47.72 1974 44.42 1975 30.75 1976 30.85 1977 31.99 1978 60.93 1979 51.44 1980 37.96 1981 31.67 1982 30.59 1983 38.06 1984 38.17 1985 43.81 1986 34.99 1987 30.48 1988 36.79 1989 28.73 1990 26.73 1991 27.65 1992 31.77 1993 25.28 1994 30.49 1995 34.34 1996 42.95 1997 41.86 1998 41.1 1999 41.24 2000 41.68 2001 40.94 2002 42.68 2003 42.47 2004 43.51 2005 42.63 2006 39.13 2007 50.97 2008 52.76 2009 54.33 2010 54.66 2011 55.45 2012 49.75 2013 51.39