Year Percent 2002-01-01 3.6750000000000000 2003-01-01 3.6260000000000003 2004-01-01 3.8600000000000000 2005-01-01 3.2900000000000000 2006-01-01 4.2500000000000000 2007-01-01 4.9100000000000000 2008-01-01 5.0200000000000000 2009-01-01 5.5000000000000000 2010-01-01 6.1400000000000000 2011-01-01 6.8000000000000000 2012-01-01 7.2900000000000000 2013-01-01 0.8600000000000000 2014-01-01 0.8700000000000000 2015-01-01 0.9200000000000000