Year	Years
1960	2.462
1961	2.023
1962	1.614
1963	1.876
1964	1.812
1965	2.324
1966	2.398
1967	2.415
1968	2.55
1969	3.262
1970	3.061
1971	2.937
1972	2.391
1973	1.991
1974	1.599
1975	1.584
1976	1.888
1977	1.233
1978	1.253
1979	-1.002
1980	-1.361
1981	-1.508
1982	-1.905
1983	-1.217
1984	-1.477
1985	-2.902
1986	-3.149
1987	-4.071
1988	-4.542
1989	-3.566
1990	-3.031
1991	-4.289
1992	-4.2
1993	-5.184
1994	-5.316
1995	-4.369
1996	-4.25
1997	-3.441
1998	-2.756
1999	-1.701
2000	-1.236
2001	0.09476
2002	-0.08676
2003	0.4533
2004	0.6678