Year	Percent
1991-01-01	26.1619177196863
1992-01-01	26.1108022793167
1993-01-01	27.6621069036612
1994-01-01	28.7802529473545
1995-01-01	30.0433866554591
1996-01-01	26.8557507328448
1997-01-01	25.4961088989278
1998-01-01	26.1465151053301
1999-01-01	24.5142269306991
2000-01-01	26.4834176849232
2001-01-01	27.0606315854942
2002-01-01	27.4573667320399
2003-01-01	27.3469900976201
2004-01-01	25.5039940536189
2005-01-01	25.6041557494843
2006-01-01	24.9628292625782
2007-01-01	23.7306455448234
2008-01-01	24.0487635740497
2009-01-01	23.1716511915970
2010-01-01	24.4590573148800
2011-01-01	25.9171889409692
2012-01-01	27.3581380798246
2013-01-01	26.8652875410306
2014-01-01	26.5424481500540
2015-01-01	27.1106259837961
2016-01-01	26.1115840862327
2017-01-01	26.1376659417773