Year Percent 1973-01-01 61.28520000000000 1974-01-01 63.05040000000000 1975-01-01 62.66900000000000 1976-01-01 63.26360000000000 1977-01-01 63.80750000000000 1978-01-01 60.30160000000000 1979-01-01 60.66090000000000 1980-01-01 62.82430000000000 1981-01-01 68.04600000000000 1982-01-01 71.40020000000000 1983-01-01 72.08850000000000 1984-01-01 73.92330000000000 1985-01-01 70.03750000000000 1986-01-01 62.92300000000000 1987-01-01 61.16520000000000 1988-01-01 59.93970000000000 1989-01-01 58.84650000000000 1990-01-01 57.24700000000000 1991-01-01 65.00110000000000 1992-01-01 72.60140000000000 1993-01-01 75.86020000000000 1994-01-01 77.59940000000000 1995-01-01 81.52820000000000 1996-01-01 86.23940000000000 1997-01-01 87.87250000000000 1998-01-01 91.75180000000000 1999-01-01 103.29100000000000 2000-01-01 118.84700000000001 2001-01-01 119.64200000000001 2002-01-01 120.09899999999999 2003-01-01 123.78900000000000 2004-01-01 123.67100000000000 2005-01-01 125.68900000000000 2006-01-01 132.29200000000000 2007-01-01 139.81400000000000 2008-01-01 152.39900000000000 2009-01-01 164.54800000000000 2010-01-01 169.52800000000000 2011-01-01 177.19299999999998 2012-01-01 180.24599999999998 2013-01-01 169.57400000000000 2014-01-01 157.27900000000000 2015-01-01 143.94899999999998 2016-01-01 134.52100000000002