Year Percent 1989-01-01 27.713700000000000 1990-01-01 29.968300000000000 1991-01-01 33.558900000000000 1992-01-01 34.423900000000000 1993-01-01 36.205999999999996 1994-01-01 38.763100000000000 1995-01-01 36.576000000000000 1996-01-01 35.885100000000000 1997-01-01 38.797000000000000 1998-01-01 42.968800000000000 1999-01-01 44.383100000000000 2000-01-01 36.661200000000000 2001-01-01 38.760100000000000 2002-01-01 37.711900000000000 2003-01-01 35.379400000000000 2004-01-01 31.461500000000000 2005-01-01 30.230800000000000 2006-01-01 26.818700000000000 2007-01-01 28.401500000000000 2008-01-01 26.419600000000000 2009-01-01 27.617900000000000 2010-01-01 22.189700000000000 2011-01-01 24.444900000000000 2012-01-01 27.871900000000000 2013-01-01 31.609200000000000 2014-01-01 33.946200000000000 2015-01-01 33.934200000000000 2016-01-01 36.407400000000000