Year	Percent
1975-01-01	75.3579
1976-01-01	76.0120
1977-01-01	70.4089
1978-01-01	67.3140
1979-01-01	60.9458
1980-01-01	60.0156
1981-01-01	75.5153
1982-01-01	78.4811
1983-01-01	77.5199
1984-01-01	76.5271
1985-01-01	74.3945
1986-01-01	67.6873
1987-01-01	57.8966
1988-01-01	62.0586
1989-01-01	75.6810
1990-01-01	83.9630
1991-01-01	84.4460
1992-01-01	82.5253
1993-01-01	85.5773
1994-01-01	90.2515
1995-01-01	86.6132
1996-01-01	81.9231
1997-01-01	81.7825
1998-01-01	83.9235
1999-01-01	82.7496
2000-01-01	85.3927
2001-01-01	86.5145
2002-01-01	78.2998
2003-01-01	69.9971
2004-01-01	66.2549
2005-01-01	66.6375
2006-01-01	66.8638
2007-01-01	65.3737
2008-01-01	64.4421
2009-01-01	63.9658
2010-01-01	64.9975
2011-01-01	68.0930
2012-01-01	66.3817
2013-01-01	62.6767
2014-01-01	59.3756
2015-01-01	56.0116
2016-01-01	52.6214