Year Percent 1996-01-01 18.033800000000000 1997-01-01 28.744400000000000 1998-01-01 35.152300000000000 1999-01-01 12.469900000000000 2000-01-01 16.115600000000000 2001-01-01 16.031500000000000 2002-01-01 20.828100000000000 2003-01-01 17.889200000000000 2004-01-01 27.346999999999998 2005-01-01 27.507400000000000 2006-01-01 40.977800000000000 2007-01-01 32.560500000000000 2008-01-01 21.752100000000000 2009-01-01 42.430700000000000 2010-01-01 39.407500000000000 2011-01-01 38.589000000000000 2012-01-01 31.838700000000000 2013-01-01 27.633800000000000 2014-01-01 24.337200000000000