Year	Years
1960	2.586
1961	3.577
1962	3.987
1963	3.358
1964	3.794
1965	4.343
1966	4.382
1967	4.317
1968	4.488
1969	4.199
1970	3.789
1971	3.4
1972	3.275
1973	3.611
1974	2.556
1975	1.963
1976	2.349
1977	2.128
1978	1.991
1979	1.725
1980	1.451
1981	1.025
1982	0.9096
1983	0.7977
1984	1.381
1985	1.983
1986	1.787
1987	1.701
1988	1.672
1989	1.389
1990	1.559
1991	1.899
1992	1.785
1993	1.524
1994	1.682
1995	1.604
1996	1.427
1997	1.745
1998	1.815
1999	2.017
2000	2.284
2001	2.201
2002	2.036
2003	2.14
2004	1.777