Year	Percent
1986-01-01	79.1905047914150
1987-01-01	79.6073322866284
1988-01-01	77.9492729053334
1989-01-01	76.3660092781779
1990-01-01	75.9306406557186
1991-01-01	74.4748156684007
1992-01-01	74.2841446643721
1993-01-01	74.5183253112982
1994-01-01	75.7193209155916
1995-01-01	77.2300712180485
1996-01-01	77.9382399061222
1997-01-01	77.3511033741388
1998-01-01	76.2638357323796
1999-01-01	77.1066673553672
2000-01-01	78.2137293002195
2001-01-01	78.8601189456594
2002-01-01	79.2894499883602
2003-01-01	79.4189222333724
2004-01-01	80.3716939900245
2005-01-01	81.5040114470935
2006-01-01	81.6986901854854
2007-01-01	81.8529011175132
2008-01-01	81.7900758250294
2009-01-01	80.4741557289085
2010-01-01	79.8628204870105
2011-01-01	80.3909095498566
2012-01-01	79.6943596916959
2013-01-01	80.8083517449368
2014-01-01	81.7448201393045
2015-01-01	81.6668277725218
2016-01-01	83.0933217459706
2017-01-01	84.1145312202554