Year	Percent
1999-01-01	21.82
2000-01-01	23.79
2001-01-01	24.65
2002-01-01	25.42
2003-01-01	27.84
2004-01-01	30.80
2005-01-01	35.90
2006-01-01	35.26
2007-01-01	31.51
2008-01-01	29.57
2009-01-01	35.65
2010-01-01	36.57
2011-01-01	35.77
2012-01-01	37.42
2013-01-01	39.96
2014-01-01	43.35
2015-01-01	46.17