Year	per person
1800	1.48
1820	1.48
1913	1.795
1950	1.938
1951	1.932
1952	1.929
1953	1.929
1954	2.008
1955	1.804
1956	1.904
1957	1.888
1958	2.068
1959	1.852
1960	2.049
1961	2.203
1962	2.35
1963	2.492
1964	2.627
1965	2.751
1966	2.912
1967	3.037
1968	3.158
1969	3.281
1970	3.401
1971	3.503
1972	3.362
1973	3.201
1974	3.203
1975	3.358
1976	3.536
1977	3.81
1978	3.939
1979	4.272
1980	4.746
1981	3.356
1982	4.145
1983	3.701
1984	3.32
1985	3.511
1986	3.473
1987	3.326
1988	3.307
1989	3.286
1990	3.283
1991	3.199
1992	3.133
1993	3.085
1994	3.069
1995	3.033
1996	2.994
1997	2.937
1998	2.91
1999	2.897
2000	2.896
2001	2.92
2002	2.967
2003	3.062
2004	3.149
2005	3.202
2006	3.36
2007	3.505
2008	3.65
2009	3.736