Year	Measure
1960	0.5127
1961	0.4929
1962	0.4845
1963	0.4751
1964	0.5092
1965	0.516
1966	0.561
1967	0.5617
1968	0.5595
1969	0.6069
1970	0.6261
1971	0.6336
1972	0.699
1973	0.7401
1974	0.7918
1975	0.7523
1976	0.781
1977	0.7989
1978	0.8437
1979	0.8656
1980	0.8808
1981	0.9234
1982	0.8861
1983	0.905
1984	0.9633
1985	1.01
1986	1.02
1987	1.024
1988	0.9811
1989	0.9166
1990	0.9211
1991	0.9449
1992	0.9583
1993	0.9692
1994	0.9776
1995	0.9857
1996	1.034
1997	1.01
1998	0.9476
1999	0.9785
2000	1.005
2001	0.9255
2002	0.9636
2003	0.9179
2004	0.9174
2005	0.9685
2006	0.9299
2007	0.9584
2008	0.9657
2009	0.9413
2010	0.8884
2011	0.9422