Year	Percent
1961-01-01	98.9383
1962-01-01	99.0950
1963-01-01	98.9246
1964-01-01	98.3390
1965-01-01	98.8150
1966-01-01	99.0448
1967-01-01	98.2085
1968-01-01	93.9335
1969-01-01	90.3485
1970-01-01	88.9692
1971-01-01	91.3086
1972-01-01	93.1161
1973-01-01	95.1111
1974-01-01	96.6890
1975-01-01	97.2723
1976-01-01	97.6205
1977-01-01	98.0687
1978-01-01	96.9978
1979-01-01	93.7744
1980-01-01	94.2598
1981-01-01	97.4389
1982-01-01	97.0885
1983-01-01	95.6289
1984-01-01	94.9799
1985-01-01	96.2578
1986-01-01	98.6759
1987-01-01	96.8679
1988-01-01	96.8480
1989-01-01	99.1749
1990-01-01	99.3596
1991-01-01	99.9771
1992-01-01	99.9833
1993-01-01	99.6198
1994-01-01	99.6453
1995-01-01	99.9924
1996-01-01	99.9963
1997-01-01	99.9963
1998-01-01	99.9963
1999-01-01	97.9978
2000-01-01	96.1017
2001-01-01	95.6879
2002-01-01	95.6126
2003-01-01	95.3388
2004-01-01	95.3681
2005-01-01	94.9614
2006-01-01	93.7375
2007-01-01	93.7689
2008-01-01	94.6236
2009-01-01	94.2155
2010-01-01	93.8630
2011-01-01	95.3029
2012-01-01	96.3616
2013-01-01	97.0794
2014-01-01	97.9302
2015-01-01	98.4733
2016-01-01	98.6908