Year	Percent
1998-01-01	35.26253128
1999-01-01	45.27687454
2000-01-01	51.34048080
2001-01-01	39.75576401
2002-01-01	45.78651810
2003-01-01	55.21108627
2004-01-01	64.52380371
2005-01-01	70.92555237
2006-01-01	72.08296967
2007-01-01	71.73731995
2008-01-01	63.84950638
2009-01-01	58.29787445
2010-01-01	59.39635849
2011-01-01	61.31805038
2012-01-01	60.90955734
2013-01-01	67.85713959