Year Percent 1980-01-01 9.0928700000000000 1981-01-01 9.5119899999999990 1982-01-01 8.7619200000000000 1983-01-01 6.5771500000000000 1984-01-01 5.7016900000000000 1985-01-01 7.0119399999999990 1986-01-01 6.1922200000000000 1987-01-01 4.2118199999999995 1988-01-01 2.6167200000000000 1989-01-01 1.8109000000000000 1990-01-01 0.9307219999999999 1991-01-01 2.3111700000000000 1992-01-01 2.1657400000000000 1993-01-01 2.1972900000000000 1994-01-01 1.4799900000000000 1995-01-01 1.2587600000000000 1996-01-01 1.7635000000000000 1997-01-01 2.7840900000000000 1998-01-01 3.5060500000000000 1999-01-01 5.3634200000000000 2000-01-01 6.3050400000000000 2001-01-01 7.1798199999999990 2002-01-01 8.8312800000000000 2003-01-01 10.5858000000000000 2004-01-01 11.9948000000000000 2005-01-01 10.6975000000000000 2006-01-01 10.9676000000000000 2007-01-01 8.5418700000000000 2008-01-01 8.0268500000000000 2009-01-01 8.3534800000000010 2010-01-01 8.7153500000000000 2011-01-01 9.8005100000000010 2012-01-01 12.8842000000000000 2013-01-01 11.1721000000000000 2014-01-01 12.4047000000000000 2015-01-01 14.9350000000000000 2016-01-01 20.8801000000000000