Year	Percent
2000-01-01	20.02
2001-01-01	21.84
2002-01-01	23.15
2003-01-01	25.45
2004-01-01	26.45
2005-01-01	28.28
2006-01-01	28.41
2007-01-01	29.20
2008-01-01	26.99
2009-01-01	31.20
2010-01-01	34.32
2011-01-01	32.51
2012-01-01	34.48
2013-01-01	35.96
2014-01-01	37.51
2015-01-01	37.79