Year	per person
1800	1.135
1820	1.135
1913	1.753
1950	2.452
1951	2.512
1952	2.572
1953	2.631
1954	2.692
1955	2.755
1956	2.817
1957	2.879
1958	2.943
1959	3.005
1960	3.04
1961	3.028
1962	3.069
1963	3.13
1964	3.186
1965	3.192
1966	3.281
1967	3.308
1968	3.456
1969	3.555
1970	3.588
1971	3.617
1972	3.693
1973	3.665
1974	3.742
1975	3.843
1976	3.815
1977	3.911
1978	4.001
1979	4.096
1980	4.362
1981	4.949
1982	5.193
1983	5.399
1984	5.648
1985	5.963
1986	6.194
1987	5.708
1988	5.288
1989	4.674
1990	4.465
1991	4.174
1992	3.932
1993	3.703
1994	3.515
1995	3.539
1996	3.624
1997	3.716
1998	3.808
1999	3.883
2000	3.955
2001	4.073
2002	4.241
2003	4.314
2004	4.38
2005	4.375
2006	4.393
2007	4.413
2008	4.416
2009	4.38