Year Percent 2003-01-01 19.00790405 2004-01-01 20.45783615 2005-01-01 24.83843040 2006-01-01 27.26451111 2007-01-01 28.11198425 2008-01-01 31.72941780 2009-01-01 34.47662354 2010-01-01 36.69714355 2011-01-01 39.02056885