Year	Years
1961	1.667
1962	1.577
1963	0.9759
1964	1.898
1965	1.453
1966	2.492
1967	2.056
1968	2.019
1969	2.715
1970	2.072
1971	2.741
1972	2.321
1973	1.39
1974	1.37
1975	-0.1553
1976	-0.9415
1977	-0.2559
1978	0.131
1979	0.5515
1980	0.7979
1981	0.4458
1982	-1.002
1983	-0.8528
1984	-0.537
1985	1.065
1986	1.319
1987	0.9375
1988	0.8
1989	0.8913
1990	0.6803
1991	0.8541
1992	3.488
1993	4.528
1994	4.617
1995	5.512
1996	5.806
1997	5.946
1998	5.609
1999	4.692
2000	4.813
2001	4.44
2002	3.55
2003	3.335
2004	3.351