Year Percent 1960-01-01 8.6131300000000000 1961-01-01 8.6142600000000000 1962-01-01 8.7314200000000000 1963-01-01 9.2325600000000010 1964-01-01 7.8539300000000000 1965-01-01 10.5637000000000000 1966-01-01 13.1096000000000000 1967-01-01 13.2252000000000000 1968-01-01 11.8294000000000000 1969-01-01 12.1616000000000000 1970-01-01 12.3566000000000000 1971-01-01 11.3888000000000000 1972-01-01 11.6851000000000000 1973-01-01 10.6697000000000000 1974-01-01 6.0460400000000005 1975-01-01 6.2129800000000000 1976-01-01 5.7424300000000010 1977-01-01 5.7424300000000010 1978-01-01 5.7424300000000010 1979-01-01 5.7424300000000010 1980-01-01 5.7424300000000010 1981-01-01 5.7424300000000010 1982-01-01 5.7424300000000010 1983-01-01 5.7424300000000010 1984-01-01 5.7424300000000010 1985-01-01 5.7424300000000010 1986-01-01 5.7424300000000010 1987-01-01 5.7424300000000010 1988-01-01 5.7424300000000010 1989-01-01 5.7424300000000010 1990-01-01 5.7424300000000010 1991-01-01 5.7424300000000010 1992-01-01 5.7424300000000010 1993-01-01 5.7424300000000010 1994-01-01 5.7424300000000010 1995-01-01 5.7424300000000010 1996-01-01 5.7424300000000010 1997-01-01 5.7424300000000010 1998-01-01 5.7424300000000010 1999-01-01 5.7424300000000010 2000-01-01 5.7424300000000010 2001-01-01 5.7424300000000010 2002-01-01 5.7424300000000010 2003-01-01 5.7424300000000010 2004-01-01 5.7424300000000010 2005-01-01 5.7424300000000010 2006-01-01 2.2590400000000000 2007-01-01 2.1723500000000000 2008-01-01 2.2281700000000000 2009-01-01 3.5120900000000000 2010-01-01 4.1767800000000000 2011-01-01 4.7045300000000000 2012-01-01 5.3232599999999990 2013-01-01 5.9077500000000000 2014-01-01 6.4723400000000000 2015-01-01 8.8464100000000000 2016-01-01 9.5967700000000000