Year Percent 1995-01-01 41.7244014375000 1996-01-01 42.0293083075000 1997-01-01 41.8185535700000 1998-01-01 42.0165605100000 1999-01-01 42.8352883850000 2000-01-01 43.7349925125000 2001-01-01 43.4385487300000 2002-01-01 43.2394455025000 2003-01-01 43.5469004875000 2004-01-01 43.9292080025000 2005-01-01 45.2645150425000 2006-01-01 45.8796589950000 2007-01-01 47.0077394550000 2008-01-01 47.9818400700000 2009-01-01 48.3843979400000 2010-01-01 49.3172232200000 2011-01-01 49.6886539875000 2012-01-01 54.0750000000000 2013-01-01 54.6000000000000 2014-01-01 55.7000000000000 2015-01-01 55.9416666666667 2016-01-01 56.4250000000000 2017-01-01 56.7000000000000