Year Percent 1960-01-01 41.59520000000000 1961-01-01 42.35230000000000 1962-01-01 42.20410000000000 1963-01-01 42.50660000000000 1964-01-01 43.10710000000000 1965-01-01 43.47910000000000 1966-01-01 42.49240000000000 1967-01-01 43.15570000000000 1968-01-01 43.80550000000000 1969-01-01 43.11890000000000 1970-01-01 43.15730000000000 1971-01-01 44.01480000000000 1972-01-01 45.40490000000000 1973-01-01 44.00830000000000 1974-01-01 41.40410000000000 1975-01-01 40.33600000000000 1976-01-01 41.14790000000000 1977-01-01 41.09430000000000 1978-01-01 40.32420000000000 1979-01-01 41.52350000000000 1980-01-01 44.68340000000000 1981-01-01 44.74620000000000 1982-01-01 48.60990000000000 1983-01-01 52.18970000000000 1984-01-01 53.62890000000000 1985-01-01 58.07750000000000 1986-01-01 65.68910000000000 1987-01-01 71.10450000000000 1988-01-01 71.78399999999999 1989-01-01 75.11470000000000 1990-01-01 79.42580000000000 1991-01-01 85.42500000000000 1992-01-01 90.80000000000000 1993-01-01 95.57799999999999 1994-01-01 96.69830000000000 1995-01-01 101.15700000000001 1996-01-01 107.71600000000001 1997-01-01 113.81200000000001 1998-01-01 122.95600000000000 1999-01-01 133.37100000000000 2000-01-01 133.53600000000000 2001-01-01 133.63100000000000 2002-01-01 132.14500000000000 2003-01-01 133.84200000000000 2004-01-01 141.23600000000000 2005-01-01 143.81799999999998 2006-01-01 148.12900000000000 2007-01-01 153.66400000000000 2008-01-01 155.14900000000000 2009-01-01 157.63900000000000 2010-01-01 159.81300000000000 2011-01-01 158.22200000000000 2012-01-01 156.31500000000000 2013-01-01 161.99900000000000 2014-01-01 166.63400000000001 2015-01-01 159.02600000000000 2016-01-01 154.53200000000000