Year	Percent
1986-01-01	65.1414954516998
1987-01-01	66.6000876370604
1988-01-01	65.7561296310251
1989-01-01	64.6155251665122
1990-01-01	65.1909816213901
1991-01-01	64.5115312549627
1992-01-01	64.5570348877188
1993-01-01	64.8269297447231
1994-01-01	66.4620395572796
1995-01-01	67.8467736797713
1996-01-01	69.1481404469409
1997-01-01	68.3086326724722
1998-01-01	67.5755418505276
1999-01-01	69.1430738313705
2000-01-01	69.9218280481523
2001-01-01	71.0459515472331
2002-01-01	71.4400088377306
2003-01-01	71.5663241030036
2004-01-01	72.2402228415282
2005-01-01	73.6046946134988
2006-01-01	73.9644100179718
2007-01-01	74.2221774879292
2008-01-01	74.7859972442869
2009-01-01	74.0648093886954
2010-01-01	72.6147785892588
2011-01-01	73.4900377512116
2012-01-01	73.0805437313427
2013-01-01	74.0019905344872
2014-01-01	74.8819798395201
2015-01-01	74.9879952549674
2016-01-01	76.8592224287026
2017-01-01	78.1611600385478