Year Percent 1996-01-01 39.110200000000000 1997-01-01 35.312000000000000 1998-01-01 32.683700000000000 1999-01-01 35.090200000000000 2000-01-01 35.875700000000000 2001-01-01 36.357900000000000 2002-01-01 40.193000000000005 2003-01-01 37.696500000000000 2004-01-01 41.716800000000000 2005-01-01 41.993200000000000 2006-01-01 36.576500000000000 2007-01-01 35.345600000000000 2008-01-01 33.353100000000000 2009-01-01 29.769100000000000 2010-01-01 30.519000000000002 2011-01-01 31.677700000000000 2012-01-01 23.381300000000000 2013-01-01 29.007600000000000 2014-01-01 34.596700000000000