Year	Years
1960	1.387
1961	1.118
1962	1.102
1963	1.313
1964	2.306
1965	2.27
1966	2.129
1967	2.274
1968	2.652
1969	2.892
1970	2.967
1971	3.343
1972	3.197
1973	3.371
1974	3.017
1975	2.693
1976	2.659
1977	2.93
1978	2.88
1979	2.785
1980	2.807
1981	2.561
1982	1.771
1983	1.483
1984	1.79
1985	2.022
1986	1.77
1987	1.815
1988	1.871
1989	1.753
1990	1.539
1991	0.9713
1992	1.391
1993	1.313
1994	1.263
1995	1.119
1996	1.057
1997	1.145
1998	1.159
1999	1.512
2000	2.108
2001	2.559
2002	2.786
2003	2.745
2004	2.513