Year Percent 1973-01-01 26.504100000000000 1974-01-01 27.694400000000000 1975-01-01 25.350600000000000 1976-01-01 23.544300000000000 1977-01-01 21.500700000000000 1978-01-01 21.117200000000000 1979-01-01 21.461900000000000 1980-01-01 21.968400000000000 1981-01-01 23.750500000000000 1982-01-01 26.834400000000000 1983-01-01 31.766300000000000 1984-01-01 34.353800000000000 1985-01-01 34.847600000000000 1986-01-01 31.760400000000000 1987-01-01 31.050800000000000 1988-01-01 36.149100000000000 1989-01-01 40.957600000000000 1990-01-01 44.953800000000000 1991-01-01 46.196000000000005 1992-01-01 50.107700000000000 1993-01-01 52.227600000000000 1994-01-01 49.459900000000000 1995-01-01 48.151400000000000 1996-01-01 48.485900000000000 1997-01-01 56.997600000000000 1998-01-01 62.035300000000000 1999-01-01 65.939200000000000 2000-01-01 81.024500000000000 2001-01-01 91.855900000000000 2002-01-01 98.298999999999990 2003-01-01 114.075000000000000 2004-01-01 137.057000000000020 2005-01-01 193.238000000000000 2006-01-01 263.938000000000000 2007-01-01 263.811000000000000 2008-01-01 216.077000000000000 2009-01-01 195.252000000000000 2010-01-01 186.815999999999970 2011-01-01 166.092000000000000 2012-01-01 144.558000000000000 2013-01-01 127.150000000000000 2014-01-01 114.740000000000000 2015-01-01 102.900000000000000 2016-01-01 95.483800000000000