Year	Years
1960	1.653
1961	1.373
1962	0.9217
1963	0.6008
1964	2.747
1965	3.159
1966	2.762
1967	2.764
1968	2.726
1969	2.974
1970	2.69
1971	2.444
1972	2.997
1973	2.617
1974	1.145
1975	0.5888
1976	1.982
1977	2.695
1978	2.208
1979	2.366
1980	3.119
1981	2.944
1982	2.801
1983	3.779
1984	3.913
1985	4.582
1986	3.772
1987	3.296
1988	3.384
1989	3.412
1990	2.782
1991	3.215
1992	3.177
1993	2.826
1994	2.776
1995	2.757
1996	3.33
1997	2.885
1998	3.133
1999	3.085
2000	2.971
2001	2.794
2002	2.775
2003	2.869