Year	Percent
1991-01-01	25.4224894394204
1992-01-01	25.2125595682062
1993-01-01	26.4290733551406
1994-01-01	27.1695068578391
1995-01-01	28.0417537339737
1996-01-01	24.9456461563954
1997-01-01	24.1844856007378
1998-01-01	25.1346792867789
1999-01-01	24.0917583236755
2000-01-01	26.1450676528379
2001-01-01	27.1874278208964
2002-01-01	27.0516798705608
2003-01-01	26.3503952743861
2004-01-01	24.2580268254051
2005-01-01	25.3245289336035
2006-01-01	24.5190015968730
2007-01-01	23.3044313628921
2008-01-01	23.7211047342319
2009-01-01	23.3432406808813
2010-01-01	25.3568090162896
2011-01-01	26.2418419432862
2012-01-01	27.6705037646406
2013-01-01	26.6223455244777
2014-01-01	26.5795594866442
2015-01-01	27.3010882191493
2016-01-01	26.8283930232848
2017-01-01	27.0048730169251