Year	Percent
1975-01-01	67.3613
1976-01-01	62.2393
1977-01-01	63.4368
1978-01-01	70.4608
1979-01-01	68.2110
1980-01-01	70.7465
1981-01-01	80.7013
1982-01-01	77.5159
1983-01-01	72.7473
1984-01-01	72.5602
1985-01-01	67.9082
1986-01-01	61.6068
1987-01-01	59.1653
1988-01-01	58.0294
1989-01-01	58.5617
1990-01-01	57.9017
1991-01-01	59.2506
1992-01-01	63.8965
1993-01-01	62.4283
1994-01-01	60.4368
1995-01-01	64.9522
1996-01-01	71.5352
1997-01-01	74.1165
1998-01-01	72.7060
1999-01-01	71.8158
2000-01-01	73.2643
2001-01-01	73.0121
2002-01-01	71.9529
2003-01-01	71.4687
2004-01-01	69.8294
2005-01-01	69.4779
2006-01-01	73.5155
2007-01-01	79.4148
2008-01-01	81.1629
2009-01-01	81.3362
2010-01-01	81.5473
2011-01-01	80.2772
2012-01-01	79.6810
2013-01-01	77.4539
2014-01-01	72.3044
2015-01-01	68.9730
2016-01-01	68.7549