Year	Percent
1986-01-01	25.5198152367797
1987-01-01	26.5144996440567
1988-01-01	30.0424026724924
1989-01-01	32.2999837831519
1990-01-01	31.5213397827453
1991-01-01	32.6156597753443
1992-01-01	34.4663036705587
1993-01-01	35.3157761591531
1994-01-01	33.9822951286412
1995-01-01	32.8934031419906
1996-01-01	33.0315331431684
1997-01-01	33.2879883664846
1998-01-01	35.0564986655444
1999-01-01	37.0577586915949
2000-01-01	37.3129655605000
2001-01-01	37.0254110827191
2002-01-01	36.3552900817686
2003-01-01	37.5811656797472
2004-01-01	37.8298865524799
2005-01-01	37.6512804351869
2006-01-01	35.5816836801484
2007-01-01	35.6272338648948
2008-01-01	37.3133931843278
2009-01-01	39.2862056928675
2010-01-01	40.9136594144847
2011-01-01	41.4489970699929
2012-01-01	41.6223990364200
2013-01-01	42.0869128926550
2014-01-01	39.9336859868498
2015-01-01	38.5047224882424
2016-01-01	37.4380322872580
2017-01-01	36.5669519890279