Year	Grams per day
1961	29.1
1962	28.37
1963	28.7
1964	29.42
1965	28.61
1966	26.54
1967	24.59
1968	27.62
1969	27.11
1970	30
1971	35.12
1972	34.94
1973	36.65
1974	39.63
1975	40.88
1976	41.95
1977	40.31
1978	36.93
1979	34.55
1980	32.87
1981	32.79
1982	30.21
1983	27.19
1984	24.76
1985	27.81
1986	26.54
1987	25.77
1988	24.42
1989	22.97
1990	22.18
1991	22.55
1992	22.13
1993	24.04
1994	24.11
1995	23.79
1996	23.84
1997	22.57
1998	23.63
1999	23.12
2000	22.18
2001	16.36
2002	12.26
2003	19.11
2004	18.96
2005	18.76
2006	18.69
2007	19.44
2008	18.94
2009	22.15
2010	21.82
2011	22.19
2012	20.13
2013	20.31