Year	Years
1960	2.931
1961	3.026
1962	3.723
1963	3.131
1964	3.067
1965	2.902
1966	2.524
1967	2.858
1968	3.96
1969	4.081
1970	3.671
1971	4.002
1972	3.609
1973	3.764
1974	3.354
1975	2.894
1976	3.139
1977	2.972
1978	2.655
1979	2.273
1980	1.888
1981	1.365
1982	1.079
1983	0.8433
1984	0.7766
1985	1.09
1986	1.01
1987	0.8886
1988	0.8944
1989	1.218
1990	1.469
1991	1.894
1992	2.159
1993	2.004
1994	1.994
1995	2.015
1996	1.994
1997	2.202
1998	2.365
1999	2.306
2000	2.286
2001	2.196
2002	2.069
2003	2.008
2004	1.913