Year	Grams per day
1961	6.52
1962	8.69
1963	9.38
1964	5.68
1965	6.14
1966	6.96
1967	8.85
1968	10.15
1969	10.09
1970	9.52
1971	8.91
1972	8.15
1973	7.97
1974	6.73
1975	2.16
1976	2.54
1977	1.15
1978	1.82
1979	3.8
1980	0.79
1981	1.88
1982	1.17
1983	1.71
1984	4.45
1985	6.06
1986	6.76
1987	6.5
1988	7.67
1989	7.88
1990	8.23
1991	12.84
1992	12.03
1993	15.17
1994	22.95
1995	21.75
1996	14.47
1997	12.99
1998	12.99
1999	16.14
2000	12.76
2001	11.22
2002	13.52
2003	14.85
2004	9.82
2005	8.9
2006	9.06
2007	8.24
2008	14.53
2009	13.62
2010	14.63
2011	14.56
2012	17.17
2013	21.37