Year Percent 1999-01-01 69.404000000000000 2000-01-01 64.778800000000000 2001-01-01 76.101100000000000 2002-01-01 68.619100000000000 2003-01-01 64.334300000000000 2004-01-01 60.442700000000000 2005-01-01 53.357000000000000 2006-01-01 43.778999999999996 2007-01-01 43.230000000000000 2008-01-01 42.346600000000000 2009-01-01 61.053100000000000 2010-01-01 60.596800000000000 2011-01-01 52.410200000000000 2012-01-01 53.947600000000000 2013-01-01 57.194200000000000 2014-01-01 60.300500000000000 2015-01-01 72.919300000000000 2016-01-01 81.961500000000000