Year Percent 1999-01-01 54.215400000000000 2000-01-01 43.126000000000005 2001-01-01 48.361600000000000 2002-01-01 47.871200000000000 2003-01-01 45.275400000000000 2004-01-01 40.554200000000000 2005-01-01 35.764200000000000 2006-01-01 31.524200000000000 2007-01-01 32.518200000000000 2008-01-01 31.217000000000000 2009-01-01 40.944600000000000 2010-01-01 37.049800000000000 2011-01-01 28.855800000000000 2012-01-01 27.758200000000000 2013-01-01 30.395900000000000 2014-01-01 32.698700000000000 2015-01-01 40.478900000000000 2016-01-01 45.258400000000000