Year	Percent
1986-01-01	48.9896545354620
1987-01-01	47.1300492069067
1988-01-01	45.0899876773425
1989-01-01	41.8114514471166
1990-01-01	41.6022560030520
1991-01-01	41.4893184806920
1992-01-01	41.4627584685227
1993-01-01	44.4325995427044
1994-01-01	47.1121120564651
1995-01-01	50.1610632219018
1996-01-01	53.6057243656703
1997-01-01	54.3145170077966
1998-01-01	55.3627326015519
1999-01-01	56.5582200988754
2000-01-01	56.8267828205656
2001-01-01	60.3300288948205
2002-01-01	63.2129869834299
2003-01-01	64.3246818345351
2004-01-01	67.0472423026941
2005-01-01	69.4878042406915
2006-01-01	70.0455835372935
2007-01-01	71.8045097084968
2008-01-01	71.6287364956693
2009-01-01	71.9997741262286
2010-01-01	73.1745319446557
2011-01-01	73.6394951285604
2012-01-01	73.8408710333245
2013-01-01	74.3458578375827
2014-01-01	76.1878634594441
2015-01-01	75.2241717770327
2016-01-01	76.0960030545582
2017-01-01	78.2172341935755