Year	Percent
1986-01-01	72.1531858111278
1987-01-01	71.9791593898199
1988-01-01	69.4373329931057
1989-01-01	67.1688578503383
1990-01-01	67.1024672103203
1991-01-01	65.2660917934879
1992-01-01	64.9294524306859
1993-01-01	65.6272838851095
1994-01-01	67.4954565564738
1995-01-01	69.6557114765745
1996-01-01	70.6098950350195
1997-01-01	70.1252016902376
1998-01-01	69.0751423650631
1999-01-01	69.5535607471694
2000-01-01	70.3327279220958
2001-01-01	71.3762915416527
2002-01-01	72.0937875828540
2003-01-01	72.1554090096211
2004-01-01	73.1646336550066
2005-01-01	74.2186905711438
2006-01-01	74.7672579326662
2007-01-01	75.1312679024174
2008-01-01	74.5926760260536
2009-01-01	72.8003935499602
2010-01-01	72.2110369661958
2011-01-01	72.5221519048454
2012-01-01	71.9759239928866
2013-01-01	72.8432242126954
2014-01-01	74.2393542901556
2015-01-01	74.2822474874512
2016-01-01	75.5717546693894
2017-01-01	76.8757192663961