Year	Measure
1971	0.00753
1972	0.0092
1973	0.01056
1974	0.01142
1975	0.01164
1976	0.01161
1977	0.01222
1978	0.01633
1979	0.01812
1980	0.01854
1981	0.01887
1982	0.01885
1983	0.01796
1984	0.01833
1985	0.02655
1986	0.0282
1987	0.03349
1988	0.03538
1989	0.03607
1990	0.04008
1991	0.03955
1992	0.03649
1993	0.03661
1994	0.02872
1995	0.0258
1996	0.03072
1997	0.03072
1998	0.02773
1999	0.03014
2000	0.03125
2001	0.02579
2002	0.02138
2003	0.02265
2004	0.01786
2005	0.02147
2006	0.02536
2007	0.02659
2008	0.02697
2009	0.03228
2010	0.03355