Year Percent 1995-01-01 65.5897893975000 1996-01-01 64.3472736925000 1997-01-01 61.7288755725000 1998-01-01 59.4924428625000 1999-01-01 60.1388655400000 2000-01-01 58.7269328450000 2001-01-01 60.3704113450000 2002-01-01 60.8720739475000 2003-01-01 60.9836959025000 2004-01-01 63.0136313500000 2005-01-01 62.9120036250000 2006-01-01 65.2543571200000 2007-01-01 67.1946017325000 2008-01-01 68.4316614950000 2009-01-01 68.0462655775000 2010-01-01 68.7511691100000 2011-01-01 70.7245969100000 2012-01-01 71.6166666666667 2013-01-01 72.8333333333334 2014-01-01 72.9000000000000 2015-01-01 73.2166666666667 2016-01-01 73.3833333333334 2017-01-01 74.4166666666666