Year	Percent
1986-01-01	81.6157450097488
1987-01-01	82.0325670845711
1988-01-01	81.3928631573273
1989-01-01	80.7526168830654
1990-01-01	80.9451856255272
1991-01-01	81.3403186118806
1992-01-01	81.2663838674073
1993-01-01	80.9649598714589
1994-01-01	81.2305693744998
1995-01-01	81.4914549916649
1996-01-01	82.1003694946353
1997-01-01	81.8383607435106
1998-01-01	81.4476269933471
1999-01-01	81.7493360251686
2000-01-01	82.0354207359784
2001-01-01	82.3429561280797
2002-01-01	82.6928659867110
2003-01-01	82.4027291196094
2004-01-01	82.8473491840547
2005-01-01	83.8310658726571
2006-01-01	83.9851391708969
2007-01-01	83.9798783351541
2008-01-01	84.1960930579730
2009-01-01	84.0203667494217
2010-01-01	83.7368658214648
2011-01-01	84.2494691434541
2012-01-01	83.8309955154167
2013-01-01	84.5425760279255
2014-01-01	85.3335371937944
2015-01-01	85.1565338426638
2016-01-01	86.4623037117763
2017-01-01	87.1809983854411