Year Percent 1980-01-01 4.9972199999999996 1981-01-01 4.7617800000000000 1982-01-01 5.3908000000000000 1983-01-01 7.3937399999999990 1984-01-01 6.5856800000000000 1985-01-01 7.2312000000000000 1986-01-01 6.5717500000000000 1987-01-01 7.6468700000000000 1988-01-01 7.4634000000000000 1989-01-01 6.3741100000000000 1990-01-01 6.1886000000000000 1991-01-01 7.9322300000000010 1992-01-01 7.2390500000000000 1993-01-01 7.4028199999999990 1994-01-01 5.2187600000000000 1995-01-01 3.7498800000000000 1996-01-01 3.7454500000000000 1997-01-01 3.5932699999999995 1998-01-01 3.3071500000000000 1999-01-01 4.3175900000000000 2000-01-01 4.5800400000000000 2001-01-01 6.8464199999999990 2002-01-01 9.8517700000000000 2003-01-01 11.2578000000000000 2004-01-01 10.6428000000000000 2005-01-01 9.7992200000000000 2006-01-01 10.7019000000000000 2007-01-01 9.1741400000000000 2008-01-01 11.0201000000000000 2009-01-01 8.4043600000000000 2010-01-01 9.4058700000000000 2011-01-01 10.4130000000000000 2012-01-01 11.0064000000000000 2013-01-01 11.3025000000000000 2014-01-01 9.7078400000000000 2015-01-01 10.9886000000000000 2016-01-01 10.2468000000000000