Year Percent 2004-01-01 0.5456680000000000 2005-01-01 0.6043940000000000 2006-01-01 0.7240370000000000 2007-01-01 0.9765360000000001 2008-01-01 1.7306099999999998 2009-01-01 2.4109700000000003 2010-01-01 2.8783600000000000 2011-01-01 3.8007800000000005 2012-01-01 4.7487300000000000 2013-01-01 5.6646300000000010 2014-01-01 6.6470699999999990 2015-01-01 7.7242500000000000 2016-01-01 8.8967500000000000