Year Percent 1960-01-01 46.491400000000000 1961-01-01 42.376999999999995 1962-01-01 39.073400000000000 1963-01-01 37.354300000000000 1964-01-01 32.533000000000000 1965-01-01 29.169400000000000 1966-01-01 30.055400000000000 1967-01-01 32.994600000000000 1968-01-01 36.447300000000000 1969-01-01 33.893900000000000 1970-01-01 30.462600000000000 1971-01-01 28.020400000000000 1972-01-01 28.225700000000000 1973-01-01 26.067900000000000 1974-01-01 27.300800000000000 1975-01-01 25.125800000000000 1976-01-01 23.304000000000002 1977-01-01 21.294200000000000 1978-01-01 20.981700000000000 1979-01-01 21.323500000000000 1980-01-01 21.702100000000000 1981-01-01 23.322200000000000 1982-01-01 26.329800000000000 1983-01-01 31.163200000000000 1984-01-01 33.823700000000000 1985-01-01 34.467100000000000 1986-01-01 31.465700000000000 1987-01-01 30.540500000000000 1988-01-01 35.272500000000000 1989-01-01 39.347400000000000 1990-01-01 41.404300000000000 1991-01-01 41.531200000000000 1992-01-01 45.196900000000000 1993-01-01 46.475100000000000 1994-01-01 44.247200000000000 1995-01-01 44.762000000000000 1996-01-01 45.942900000000000 1997-01-01 54.763100000000000 1998-01-01 60.623000000000005 1999-01-01 64.887700000000000 2000-01-01 80.204000000000000 2001-01-01 90.788500000000000 2002-01-01 96.981400000000000 2003-01-01 112.571000000000000 2004-01-01 135.916000000000000 2005-01-01 192.658000000000000 2006-01-01 263.268000000000000 2007-01-01 261.464000000000000 2008-01-01 211.424000000000000 2009-01-01 183.567000000000000 2010-01-01 169.180999999999980 2011-01-01 149.819000000000000 2012-01-01 129.380000000000000 2013-01-01 113.480000000000000 2014-01-01 101.052000000000000 2015-01-01 89.380300000000000 2016-01-01 84.259200000000000