Year Percent 1964-01-01 67.52500000000000 1965-01-01 68.51830000000000 1966-01-01 70.49260000000000 1967-01-01 70.03399999999999 1968-01-01 60.80150000000000 1969-01-01 60.01200000000000 1970-01-01 64.41740000000000 1971-01-01 71.99300000000000 1972-01-01 76.18380000000000 1973-01-01 83.39290000000000 1974-01-01 83.39290000000000 1975-01-01 83.39290000000000 1976-01-01 201.32200000000000 1977-01-01 120.20800000000000 1978-01-01 145.04399999999998 1979-01-01 144.61800000000000 1980-01-01 154.14400000000000 1981-01-01 180.28200000000000 1982-01-01 312.33200000000000 1983-01-01 312.33200000000000 1984-01-01 312.33200000000000 1985-01-01 312.33200000000000 1986-01-01 312.33200000000000 1987-01-01 312.33200000000000 1988-01-01 128.67000000000000 1989-01-01 160.30000000000000 1990-01-01 145.92500000000000 1991-01-01 102.85200000000000 1992-01-01 84.11670000000000 1993-01-01 96.70180000000000 1994-01-01 108.12000000000000 1995-01-01 112.30600000000000 1996-01-01 120.75600000000000 1997-01-01 125.44100000000000 1998-01-01 137.59400000000000 1999-01-01 156.47200000000000 2000-01-01 174.77400000000000 2001-01-01 186.27700000000002 2002-01-01 185.34500000000000 2003-01-01 196.90599999999998 2004-01-01 204.00300000000000 2005-01-01 215.92200000000000 2006-01-01 224.13600000000000 2007-01-01 231.96800000000000 2008-01-01 216.50099999999998 2009-01-01 202.81599999999997 2010-01-01 216.26300000000000 2011-01-01 228.77800000000000 2012-01-01 222.97400000000002 2013-01-01 225.60800000000000 2014-01-01 234.64100000000000 2015-01-01 235.19500000000000 2016-01-01 243.03599999999997