Year Percent 1995-01-01 68.9586732250000 1996-01-01 68.2270738900000 1997-01-01 67.7855669750000 1998-01-01 67.3370634000000 1999-01-01 67.0488841125000 2000-01-01 67.0860851325000 2001-01-01 66.9033958800000 2002-01-01 66.3151875275000 2003-01-01 66.3241454425000 2004-01-01 66.8173461425000 2005-01-01 66.7900836650000 2006-01-01 67.2327075800000 2007-01-01 67.9766567800000 2008-01-01 68.0521753000000 2009-01-01 67.7696626100000 2010-01-01 68.1505570225000 2011-01-01 68.2432017400000 2012-01-01 75.8833333333334 2013-01-01 75.9583333333333 2014-01-01 76.0666666666667 2015-01-01 76.1083333333333 2016-01-01 75.6500000000000 2017-01-01 75.6250000000000