Year Percent 1990-01-01 26.752700000000000 1991-01-01 35.321999999999996 1992-01-01 38.613900000000000 1993-01-01 37.673400000000000 1994-01-01 43.784500000000000 1995-01-01 49.609100000000000 1996-01-01 50.905000000000000 1997-01-01 48.175800000000000 1998-01-01 48.463300000000000 1999-01-01 48.367600000000000 2000-01-01 43.895500000000000 2001-01-01 35.386600000000000 2002-01-01 40.771300000000000 2003-01-01 43.785500000000000 2004-01-01 42.771000000000000 2005-01-01 35.904600000000000 2006-01-01 37.220300000000000 2007-01-01 29.849900000000000 2008-01-01 22.555000000000000 2009-01-01 28.064200000000000 2010-01-01 27.113600000000000 2011-01-01 22.504600000000000 2012-01-01 24.872100000000000 2013-01-01 25.420400000000000 2014-01-01 21.652200000000000 2015-01-01 24.091200000000000 2016-01-01 21.169800000000000