Year Percent 2004-01-01 5.6685500000000000 2005-01-01 4.7073199999999990 2006-01-01 3.9990600000000000 2007-01-01 3.4702200000000000 2008-01-01 1.3301500000000000 2009-01-01 4.7430900000000005 2010-01-01 12.0424000000000000 2011-01-01 13.2912000000000000 2012-01-01 17.6256000000000000 2013-01-01 20.1635000000000000 2014-01-01 21.1393000000000000 2015-01-01 25.2511000000000000 2016-01-01 32.9935000000000000