Year Percent 1991-01-01 40.0730018615723 1992-01-01 39.9939994812012 1993-01-01 39.9609985351563 1994-01-01 39.8800010681152 1995-01-01 39.8549995422363 1996-01-01 39.7599983215332 1997-01-01 40.1100006103516 1998-01-01 40.1010017395020 1999-01-01 40.3819999694824 2000-01-01 40.7249984741211 2001-01-01 41.1710014343262 2002-01-01 41.6349983215332 2003-01-01 42.0740013122559 2004-01-01 42.3400001525879 2005-01-01 42.4469985961914 2006-01-01 42.4970016479492 2007-01-01 42.3919982910156 2008-01-01 42.7010002136230 2009-01-01 42.9780006408691 2010-01-01 42.8069992065430 2011-01-01 42.9109992980957 2012-01-01 43.1370010375977 2013-01-01 43.4230003356934 2014-01-01 43.6240005493164 2015-01-01 43.8050003051758 2016-01-01 44.0419998168945 2017-01-01 44.0569992065430