Year Percent 1976-01-01 128.34700000000000 1977-01-01 122.52000000000000 1978-01-01 109.83500000000000 1979-01-01 85.92390000000000 1980-01-01 70.95990000000000 1981-01-01 56.07560000000000 1982-01-01 60.93970000000000 1983-01-01 72.07270000000000 1984-01-01 69.38340000000000 1985-01-01 84.46280000000000 1986-01-01 105.02100000000000 1987-01-01 103.44000000000000 1988-01-01 93.10090000000000 1989-01-01 109.00500000000000 1990-01-01 119.95700000000001 1991-01-01 108.81200000000001 1992-01-01 100.27400000000000 1993-01-01 97.84680000000000 1994-01-01 90.99190000000000 1995-01-01 94.73640000000000 1996-01-01 102.28399999999999 1997-01-01 99.96200000000000 1998-01-01 100.34400000000000 1999-01-01 96.97170000000000 2000-01-01 88.33160000000000 2001-01-01 92.76640000000000 2002-01-01 97.06740000000000 2003-01-01 91.11340000000000 2004-01-01 89.41420000000000 2005-01-01 93.62860000000000 2006-01-01 90.48650000000000 2007-01-01 91.39920000000000 2008-01-01 92.15840000000000 2009-01-01 92.10410000000000 2010-01-01 86.25410000000000 2011-01-01 80.67120000000000 2012-01-01 78.71340000000000 2013-01-01 73.06700000000000 2014-01-01 70.92890000000000 2015-01-01 74.76740000000000 2016-01-01 77.72840000000000