Year Percent 1998-01-01 22.197700000000000 1999-01-01 25.410000000000000 2000-01-01 28.200000000000000 2001-01-01 20.600000000000000 2002-01-01 32.359600000000000 2003-01-01 28.819800000000000 2004-01-01 30.116999999999997 2005-01-01 30.320500000000000 2006-01-01 33.700800000000000 2007-01-01 35.909100000000000 2008-01-01 34.064800000000000 2009-01-01 33.128600000000000 2010-01-01 39.437200000000000 2011-01-01 35.577400000000000 2012-01-01 29.215700000000000