Year	per person
1800	0.821
1820	0.821
1913	1.269
1950	1.542
1951	1.586
1952	1.63
1953	1.673
1954	1.718
1955	1.764
1956	1.81
1957	1.856
1958	1.9
1959	1.947
1960	2.075
1961	2.398
1962	2.316
1963	2.145
1964	2.747
1965	3.085
1966	3.057
1967	3.117
1968	3.341
1969	3.238
1970	3.518
1971	3.494
1972	3.48
1973	3.208
1974	3.476
1975	3.197
1976	3.39
1977	3.284
1978	3.207
1979	3.286
1980	3.344
1981	3.394
1982	3.248
1983	3.326
1984	3.01
1985	3.018
1986	3.106
1987	3.118
1988	3.147
1989	3.177
1990	3.056
1991	3.048
1992	2.985
1993	3.027
1994	3.063
1995	3.119
1996	3.226
1997	3.252
1998	3.279
1999	3.313
2000	3.379
2001	3.425
2002	3.463
2003	3.551
2004	3.629
2005	3.708
2006	4.036
2007	3.982
2008	4.031
2009	3.894