Year	per person
1800	1.452
1820	1.458
1950	1.691
1951	1.703
1952	1.714
1953	1.727
1954	1.737
1955	1.748
1956	1.757
1957	1.765
1958	1.773
1959	1.781
1960	1.789
1961	1.799
1962	1.811
1963	1.827
1964	1.836
1965	1.849
1966	1.87
1967	1.891
1968	1.908
1969	1.931
1970	2.283
1971	2.625
1972	2.774
1973	3.044
1974	3.148
1975	3.311
1976	3.717
1977	4.013
1978	4.234
1979	4.347
1980	4.252
1981	4.387
1982	4.337
1983	4.457
1984	4.496
1985	4.329
1986	4.289
1987	4.324
1988	4.364
1989	4.367
1990	4.218
1991	4.077
1992	4.122
1993	4.083
1994	4.024
1995	4.321
1996	4.436
1997	4.644
1998	4.714
1999	4.734
2000	4.862
2001	4.88
2002	4.901
2003	4.912
2004	4.936
2005	4.991
2006	4.995
2007	5.007
2008	5.035
2009	5.073