Year	Years
1970	2.41
1971	2.593
1972	2.634
1973	3.579
1974	4.133
1975	6.936
1976	8.578
1977	8.927
1978	7.851
1979	5.939
1980	4.968
1981	4.406
1982	4.256
1983	2.262
1984	1.16
1985	-1.728
1986	-4.474
1987	-6.169
1988	-4.692
1989	-3.695
1990	-2.038
1991	-1.836
1992	-0.3314
1993	-1.404
1994	-6.017
1995	-4.997
1996	0.2832
1997	9.783
1998	11.04
1999	13.58
2000	15.02
2001	19.21
2002	21.97
2003	22.23