Year Percent 1996-01-01 34.917000000000000 1997-01-01 31.733900000000000 1998-01-01 45.444500000000000 1999-01-01 46.222800000000000 2000-01-01 52.696000000000005 2001-01-01 56.081400000000000 2002-01-01 33.450000000000000 2003-01-01 32.295800000000000 2004-01-01 36.960900000000000 2005-01-01 40.142400000000000 2006-01-01 37.161600000000000 2007-01-01 36.984400000000000 2008-01-01 34.404200000000000 2009-01-01 26.901800000000000 2010-01-01 27.336800000000000 2011-01-01 23.726400000000000 2012-01-01 25.206300000000000 2013-01-01 22.251700000000000 2014-01-01 21.566100000000000