Year Percent 1995-01-01 61.7680179825000 1996-01-01 60.9003796925000 1997-01-01 59.7809149625000 1998-01-01 58.6181059300000 1999-01-01 58.0813210875000 2000-01-01 58.3047746425000 2001-01-01 57.9315615750000 2002-01-01 56.7723159900000 2003-01-01 56.6134072150000 2004-01-01 57.4608455200000 2005-01-01 58.1716147275000 2006-01-01 59.0831234800000 2007-01-01 60.4602151425000 2008-01-01 61.4402939875000 2009-01-01 60.0381753275000 2010-01-01 61.0022194100000 2011-01-01 61.8573338250000 2012-01-01 67.9333333333333 2013-01-01 68.4416666666667 2014-01-01 68.7916666666667 2015-01-01 69.2666666666667 2016-01-01 69.3333333333333 2017-01-01 69.6000000000000