Year	Percent
1999-01-01	29.675
2000-01-01	33.200
2001-01-01	34.125
2002-01-01	35.450
2003-01-01	37.800
2004-01-01	38.400
2005-01-01	40.550
2006-01-01	41.200
2007-01-01	40.100
2008-01-01	37.725
2009-01-01	38.700
2010-01-01	38.600
2011-01-01	39.300
2012-01-01	41.375
2013-01-01	44.825
2014-01-01	49.625
2015-01-01	54.375
2016-01-01	59.650
2017-01-01	62.575