Year	Measure
1971	0.00571
1972	0.0063
1973	0.00435
1974	0.00529
1975	0.0056
1976	0.00464
1977	0.00455
1978	0.00475
1979	0.0047
1980	0.00484
1981	0.00496
1982	0.00528
1983	0.00577
1984	0.00568
1985	0.00561
1986	0.00557
1987	0.00461
1988	0.00371
1989	0.00464
1990	0.0032
1991	0.00347
1992	0.00312
1993	0.00256
1994	0.00314
1995	0.00335
1996	0.00353
1997	0.00377
1998	0.00387
1999	0.0039
2000	0.00383
2001	0.00198
2002	0.00308
2003	0.0038
2004	0.00432
2005	0.00487
2006	0.00529
2007	0.00508
2008	0.00499
2009	0.00441
2010	0.00477
