Year Percent 2000-01-01 18.30980 2001-01-01 19.89525 2002-01-01 24.26540 2003-01-01 34.03568 2004-01-01 44.61927 2005-01-01 52.50704 2006-01-01 60.17865 2007-01-01 66.77183 2008-01-01 67.34312 2009-01-01 63.42467 2010-01-01 60.40690