Year	per person
1800	1.264
1820	1.264
1913	1.953
1950	2.136
1951	2.25
1952	2.362
1953	2.369
1954	2.483
1955	2.488
1956	2.374
1957	2.414
1958	2.33
1959	2.375
1960	2.423
1961	2.446
1962	2.524
1963	2.695
1964	2.744
1965	2.859
1966	2.7
1967	2.225
1968	2.146
1969	2.654
1970	3.382
1971	3.683
1972	3.725
1973	3.939
1974	4.272
1975	4.02
1976	4.325
1977	4.346
1978	3.963
1979	4.102
1980	4.042
1981	3.599
1982	3.458
1983	3.176
1984	2.979
1985	3.157
1986	3.145
1987	3.037
1988	3.249
1989	3.365
1990	3.445
1991	3.555
1992	3.552
1993	3.536
1994	3.424
1995	3.424
1996	3.551
1997	3.563
1998	3.539
1999	3.487
2000	3.551
2001	3.574
2002	3.542
2003	3.829
2004	3.963
2005	4.149
2006	4.289
2007	4.465
2008	4.605
2009	4.735