Year Percent 1998-01-01 23.3010 1999-01-01 16.7273 2000-01-01 40.0568 2001-01-01 46.3294 2002-01-01 41.5617 2003-01-01 55.5639 2004-01-01 43.9626 2005-01-01 30.7692 2006-01-01 45.0370 2007-01-01 52.6995 2008-01-01 50.9335 2009-01-01 51.9449 2010-01-01 51.7283 2011-01-01 68.9096 2012-01-01 59.7884 2013-01-01 40.7085 2014-01-01 54.0494 2015-01-01 44.9478 2016-01-01 62.0406