Year Percent 1975-01-01 52.589600000000000 1976-01-01 43.590000000000000 1977-01-01 42.068500000000000 1978-01-01 42.426800000000000 1979-01-01 40.281000000000000 1980-01-01 41.538700000000000 1981-01-01 41.923100000000000 1982-01-01 48.845200000000000 1983-01-01 48.461200000000000 1984-01-01 41.918600000000000 1985-01-01 41.005300000000000 1986-01-01 37.905200000000000 1987-01-01 39.404900000000000 1988-01-01 39.815800000000000 1989-01-01 44.866400000000000 1990-01-01 45.142900000000000 1991-01-01 46.131100000000000 1992-01-01 46.634900000000000 1993-01-01 53.163999999999994 1994-01-01 56.278999999999996 1995-01-01 57.263400000000000 1996-01-01 61.703200000000000 1997-01-01 66.886800000000000 1998-01-01 67.360900000000000 1999-01-01 69.371300000000000 2000-01-01 74.398300000000000 2001-01-01 82.737200000000000 2002-01-01 81.670200000000000 2003-01-01 74.542900000000000 2004-01-01 72.131300000000000 2005-01-01 78.096800000000000 2006-01-01 82.804100000000000 2007-01-01 90.775800000000000 2008-01-01 107.062000000000010 2009-01-01 114.583000000000000 2010-01-01 109.607999999999990 2011-01-01 106.201000000000010 2012-01-01 111.508000000000000 2013-01-01 110.930000000000000 2014-01-01 104.420000000000000 2015-01-01 89.913600000000000 2016-01-01 82.682100000000000