Year	Percent
1999-01-01	39.2314291045961
2000-01-01	39.9707982146868
2001-01-01	39.5168603102107
2002-01-01	39.4756879443631
2003-01-01	39.3052685451631
2004-01-01	39.8142515560701
2005-01-01	40.4256059141742
2006-01-01	40.4319612743677
2007-01-01	41.2688055399328
2008-01-01	41.5208923323215
2009-01-01	40.9465171121183
2010-01-01	41.2099435888426
2011-01-01	41.0325176172282
2012-01-01	40.8906680217100
2013-01-01	40.7215036983476
2014-01-01	40.6356602204278