Year	Percent
1991-01-01	40.6076019859550
1992-01-01	40.5957887860848
1993-01-01	40.2858675313753
1994-01-01	40.0991669702952
1995-01-01	39.4064492192747
1996-01-01	39.8356565312574
1997-01-01	39.8993283897628
1998-01-01	39.4867426348541
1999-01-01	39.9724526864567
2000-01-01	39.5669565135257
2001-01-01	39.3679727166581
2002-01-01	39.3509970077122
2003-01-01	39.7646563462167
2004-01-01	40.5035824665434
2005-01-01	40.5829227690161
2006-01-01	40.8863259869560
2007-01-01	41.1551767013783
2008-01-01	40.8989257045555
2009-01-01	40.8919447426724
2010-01-01	40.2876035652253
2011-01-01	40.0084446640354
2012-01-01	39.7730988091213
2013-01-01	40.0166927666696
2014-01-01	39.5123543634445
2015-01-01	39.5344044272400
2016-01-01	39.7907645208903
2017-01-01	39.8022127165654