Year Percent 1996-01-01 21.428600000000000 1997-01-01 21.739100000000000 1998-01-01 25.000000000000000 1999-01-01 28.301900000000000 2000-01-01 27.457600000000000 2001-01-01 35.279500000000000 2002-01-01 31.397800000000000 2003-01-01 29.906900000000000 2004-01-01 38.284400000000000 2005-01-01 39.817600000000000 2006-01-01 36.923900000000000 2007-01-01 38.630700000000000 2008-01-01 31.330400000000000 2009-01-01 30.110800000000000 2010-01-01 33.071999999999996 2011-01-01 34.193200000000000 2012-01-01 32.816700000000000 2013-01-01 33.947500000000000 2014-01-01 31.722600000000000