Year	Percent
1986-01-01	19.1879502185720
1987-01-01	20.5582967047425
1988-01-01	24.6499059518468
1989-01-01	26.2171831877368
1990-01-01	27.4843264379833
1991-01-01	28.5971304199754
1992-01-01	30.3681851545789
1993-01-01	31.2243507931879
1994-01-01	29.9780365190630
1995-01-01	28.7839814509881
1996-01-01	29.4422686182738
1997-01-01	30.3357059809471
1998-01-01	32.1244962989788
1999-01-01	33.3396447889498
2000-01-01	34.1798440201868
2001-01-01	33.8262472636412
2002-01-01	33.2564245403513
2003-01-01	34.7195220961334
2004-01-01	34.3491951285006
2005-01-01	34.4869447410079
2006-01-01	32.6889618576326
2007-01-01	33.0129124669415
2008-01-01	34.5138828687254
2009-01-01	36.6795362019948
2010-01-01	39.1146887163368
2011-01-01	39.0088894577414
2012-01-01	39.5294092428872
2013-01-01	40.3171488097908
2014-01-01	37.7646440883094
2015-01-01	36.3065178152426
2016-01-01	35.0530149748304
2017-01-01	34.5648120069749