Year Percent 1973-01-01 76.33170000000000 1974-01-01 76.58630000000000 1975-01-01 80.32740000000000 1976-01-01 82.33210000000000 1977-01-01 80.05570000000000 1978-01-01 76.13440000000000 1979-01-01 75.47260000000000 1980-01-01 76.73860000000000 1981-01-01 81.27720000000000 1982-01-01 84.91860000000000 1983-01-01 82.23280000000000 1984-01-01 81.51000000000000 1985-01-01 85.50060000000000 1986-01-01 86.11700000000000 1987-01-01 88.06860000000000 1988-01-01 90.93320000000000 1989-01-01 94.75340000000000 1990-01-01 97.15720000000000 1991-01-01 96.81070000000000 1992-01-01 96.43580000000000 1993-01-01 97.32570000000000 1994-01-01 96.88240000000000 1995-01-01 97.01440000000000 1996-01-01 97.67930000000000 1997-01-01 98.32370000000000 1998-01-01 100.67299999999999 1999-01-01 107.28900000000000 2000-01-01 110.84600000000000 2001-01-01 113.20299999999999 2002-01-01 112.29200000000000 2003-01-01 117.10799999999999 2004-01-01 123.56400000000000 2005-01-01 134.92700000000002 2006-01-01 152.69799999999998 2007-01-01 166.11300000000000 2008-01-01 179.50900000000001 2009-01-01 190.11900000000003 2010-01-01 191.03900000000002 2011-01-01 193.42600000000000 2012-01-01 194.33800000000000 2013-01-01 185.79800000000000 2014-01-01 171.73500000000000 2015-01-01 154.67200000000000 2016-01-01 139.82700000000000