Year	Percent
1971-01-01	92.1053
1972-01-01	93.7627
1973-01-01	96.3556
1974-01-01	97.3316
1975-01-01	97.5217
1976-01-01	98.0825
1977-01-01	98.6412
1978-01-01	96.2897
1979-01-01	95.7497
1980-01-01	98.3811
1981-01-01	95.5998
1982-01-01	90.3593
1983-01-01	85.2551
1984-01-01	81.7547
1985-01-01	78.8775
1986-01-01	78.6196
1987-01-01	79.1348
1988-01-01	78.2153
1989-01-01	83.3895
1990-01-01	88.1257
1991-01-01	88.8086
1992-01-01	84.0938
1993-01-01	79.4988
1994-01-01	73.9509
1995-01-01	66.8001
1996-01-01	63.8269
1997-01-01	62.7738
1998-01-01	73.3484
1999-01-01	82.3970
2000-01-01	82.8738
2001-01-01	82.9385
2002-01-01	78.8884
2003-01-01	78.1641
2004-01-01	77.4670
2005-01-01	74.2397
2006-01-01	76.6162
2007-01-01	78.7268
2008-01-01	80.4002
2009-01-01	81.9299
2010-01-01	81.3216
2011-01-01	81.1742
2012-01-01	81.9572
2013-01-01	83.7857
2014-01-01	85.6219
2015-01-01	87.0593
2016-01-01	88.2072