Year	Measure
1971	0.00554
1972	0.00633
1973	0.00973
1974	0.0139
1975	0.01614
1976	0.01586
1977	0.01027
1978	0.00705
1979	0.01229
1980	0.01774
1981	0.01812
1982	0.01641
1983	0.01935
1984	0.02453
1985	0.09367
1986	0.2675
1987	0.4069
1988	0.426
1989	0.5056
1990	0.5503
1991	0.5791
1992	0.5222
1993	0.59
1994	0.6679
1995	0.7547
1996	0.785
1997	0.8713
1998	0.8531
1999	0.853
2000	0.8608
2001	0.7145
2002	0.745
2003	0.7843
2004	0.7716
2005	0.746
2006	0.7697
2007	0.7549
2008	0.7655
2009	0.7451
2010	0.7202