Year	Years
1961	1.707
1962	3.656
1963	4.637
1964	4.657
1965	3.201
1966	2.934
1967	2.19
1968	1.537
1969	1.841
1970	2.653
1971	3.476
1972	1.973
1973	2.082
1974	2.277
1975	3.35
1976	3.111
1977	3.761
1978	4.246
1979	3.952
1980	3.572
1981	3.887
1982	3.683
1983	3.143
1984	2.457
1985	2.266
1986	2.224
1987	2.11
1988	1.992
1989	1.93
1990	0.5292
1991	-0.05325
1992	0.5704
1993	0.8244
1994	1.271
1995	1.754
1996	2.234
1997	2.592
1998	3.209
1999	3.504
2000	4.623
2001	4.973
2002	4.556
2003	3.736