Year Percent 1999-01-01 40.416200000000000 2000-01-01 48.700000000000000 2001-01-01 34.900000000000000 2002-01-01 29.766100000000000 2003-01-01 18.916000000000000 2004-01-01 20.593900000000000 2005-01-01 30.644400000000000 2006-01-01 27.782400000000000 2007-01-01 29.618900000000000 2008-01-01 22.256700000000000 2009-01-01 21.977600000000000 2010-01-01 16.464100000000000 2011-01-01 6.687810000000001 2012-01-01 39.848700000000000 2013-01-01 32.100100000000000 2014-01-01 40.803200000000000 2015-01-01 38.178300000000000 2016-01-01 37.271100000000000