Year Percent 1999-01-01 25.927900000000000 2000-01-01 44.146400000000000 2001-01-01 19.033600000000000 2002-01-01 21.597700000000000 2003-01-01 30.846200000000000 2004-01-01 13.625900000000000 2005-01-01 39.335500000000000 2006-01-01 23.866100000000000 2007-01-01 33.913700000000000 2008-01-01 36.374400000000000 2009-01-01 24.582900000000000 2010-01-01 15.794300000000000 2011-01-01 30.120100000000000 2012-01-01 23.415600000000000 2013-01-01 15.405999999999999 2014-01-01 13.584300000000000 2015-01-01 8.262910000000000 2016-01-01 5.118200000000000