Year Percent 1960-01-01 9.290880000000000 1961-01-01 9.262139999999999 1962-01-01 9.400130000000000 1963-01-01 9.932480000000000 1964-01-01 10.107200000000000 1965-01-01 10.543700000000000 1966-01-01 11.173800000000000 1967-01-01 11.284200000000000 1968-01-01 11.581200000000000 1969-01-01 12.893100000000000 1970-01-01 9.149380000000000 1971-01-01 10.131000000000000 1972-01-01 10.489800000000000 1973-01-01 11.124400000000000 1974-01-01 11.471800000000000 1975-01-01 11.781700000000000 1976-01-01 11.921000000000000 1977-01-01 12.665999999999999 1978-01-01 13.566600000000000 1979-01-01 13.381900000000000 1980-01-01 12.980100000000000 1981-01-01 12.942000000000000 1982-01-01 14.545200000000000 1983-01-01 16.456000000000000 1984-01-01 17.422600000000000 1985-01-01 16.609400000000000 1986-01-01 16.686600000000000 1987-01-01 17.587700000000000 1988-01-01 18.270200000000000 1989-01-01 18.557000000000002 1990-01-01 17.423300000000000 1991-01-01 16.699800000000000 1992-01-01 17.457500000000000 1993-01-01 16.980900000000000 1994-01-01 15.711200000000000 1995-01-01 15.705700000000000 1996-01-01 17.658900000000000 1997-01-01 22.944200000000000 1998-01-01 27.949500000000000 1999-01-01 31.308700000000000 2000-01-01 32.563000000000000 2001-01-01 35.029700000000000 2002-01-01 37.040100000000000 2003-01-01 37.830000000000000 2004-01-01 38.431200000000000 2005-01-01 39.847700000000000 2006-01-01 42.478300000000000 2007-01-01 45.609100000000000 2008-01-01 46.453800000000000 2009-01-01 45.161800000000000 2010-01-01 43.541400000000000 2011-01-01 43.450800000000000 2012-01-01 44.305000000000000 2013-01-01 46.008800000000000 2014-01-01 46.711300000000000 2015-01-01 46.351600000000000 2016-01-01 47.720000000000000