Year Percent 1965-01-01 6.2624900000000010 1966-01-01 5.8050400000000000 1967-01-01 6.4967500000000000 1968-01-01 7.7732899999999990 1969-01-01 9.0220899999999990 1970-01-01 5.3613100000000000 1971-01-01 5.4372900000000000 1972-01-01 5.9786600000000000 1973-01-01 5.4974000000000000 1974-01-01 5.2750900000000005 1975-01-01 5.4406200000000000 1976-01-01 6.3606400000000000 1977-01-01 7.4258600000000010 1978-01-01 8.5999600000000010 1979-01-01 13.0614000000000000 1980-01-01 11.2142000000000000 1981-01-01 11.0204000000000000 1982-01-01 10.6679000000000000 1983-01-01 10.4223000000000000 1984-01-01 9.4009300000000000 1985-01-01 7.6619699999999990 1986-01-01 7.1509500000000000 1987-01-01 6.3329500000000000 1988-01-01 4.8036800000000000 1989-01-01 5.1124700000000000 1990-01-01 6.3196800000000000 1991-01-01 6.0373600000000000 1992-01-01 7.4872900000000000 1993-01-01 5.6968600000000000 1994-01-01 5.5061900000000000 1995-01-01 3.8092500000000000 1996-01-01 2.5104800000000000 1997-01-01 2.2923600000000000 1998-01-01 2.8579300000000000 1999-01-01 3.7202699999999997 2000-01-01 4.2829100000000000 2001-01-01 4.5861500000000000 2002-01-01 4.1796000000000000 2003-01-01 3.9453300000000002 2004-01-01 3.9348800000000000 2005-01-01 4.9011800000000000 2006-01-01 5.7891400000000000 2007-01-01 7.1834100000000000 2008-01-01 7.9947600000000000 2009-01-01 9.2096100000000010 2010-01-01 11.3426000000000000 2011-01-01 12.6118000000000000 2012-01-01 12.8970000000000000 2013-01-01 11.5493000000000000 2014-01-01 10.6096000000000000 2015-01-01 10.4112000000000000 2016-01-01 9.9978000000000000