Year Percent 1996-01-01 31.133700000000000 1997-01-01 28.368200000000000 1998-01-01 24.758800000000000 1999-01-01 33.143800000000000 2000-01-01 35.596300000000000 2001-01-01 29.637300000000000 2002-01-01 28.852200000000000 2003-01-01 34.306999999999995 2004-01-01 36.957600000000000 2005-01-01 41.015400000000000 2006-01-01 49.051700000000000 2007-01-01 39.805300000000000 2008-01-01 25.240400000000000 2009-01-01 33.878700000000000 2010-01-01 33.102900000000000 2011-01-01 33.022800000000000 2012-01-01 37.968000000000000 2013-01-01 41.282000000000000 2014-01-01 44.183200000000000