Year Percent 1973-01-01 29.02690000000000 1974-01-01 32.88710000000000 1975-01-01 29.45230000000000 1976-01-01 25.65930000000000 1977-01-01 25.32530000000000 1978-01-01 24.09950000000000 1979-01-01 23.91270000000000 1980-01-01 24.68610000000000 1981-01-01 27.41610000000000 1982-01-01 31.36680000000000 1983-01-01 34.12010000000000 1984-01-01 38.42850000000000 1985-01-01 41.62840000000000 1986-01-01 58.89480000000000 1987-01-01 76.53210000000000 1988-01-01 82.67710000000000 1989-01-01 92.91210000000000 1990-01-01 100.48600000000000 1991-01-01 101.92700000000000 1992-01-01 100.46799999999999 1993-01-01 98.54930000000000 1994-01-01 97.52640000000000 1995-01-01 93.22330000000000 1996-01-01 96.45420000000000 1997-01-01 99.32150000000000 1998-01-01 100.42299999999999 1999-01-01 102.39500000000000 2000-01-01 107.48500000000000 2001-01-01 116.34600000000000 2002-01-01 120.46400000000000 2003-01-01 123.99000000000000 2004-01-01 130.50600000000000 2005-01-01 136.91800000000000 2006-01-01 144.98200000000000 2007-01-01 158.27200000000002 2008-01-01 180.60400000000000 2009-01-01 196.12500000000000 2010-01-01 187.62000000000000 2011-01-01 177.85299999999998 2012-01-01 165.46599999999998 2013-01-01 154.49500000000000 2014-01-01 141.31600000000000 2015-01-01 132.97600000000000 2016-01-01 130.47899999999998