Year Percent 1980-01-01 1.4000800000000000 1981-01-01 1.5340000000000000 1982-01-01 1.9771599999999998 1983-01-01 2.4843800000000000 1984-01-01 3.0256300000000000 1985-01-01 4.4866900000000000 1986-01-01 4.7794900000000000 1987-01-01 5.9794300000000010 1988-01-01 5.8723199999999990 1989-01-01 8.5133100000000000 1990-01-01 9.9068500000000000 1991-01-01 9.9230800000000000 1992-01-01 8.9736700000000000 1993-01-01 7.3918399999999990 1994-01-01 6.9656800000000000 1995-01-01 6.2237000000000000 1996-01-01 6.8168300000000000 1997-01-01 6.9436399999999990 1998-01-01 7.5782500000000000 1999-01-01 7.1358600000000010 2000-01-01 5.6521200000000000 2001-01-01 5.7072300000000000 2002-01-01 5.8584700000000000 2003-01-01 5.9047100000000000 2004-01-01 5.9584100000000000 2005-01-01 5.5150600000000000 2006-01-01 6.7382100000000005 2007-01-01 7.5996399999999990 2008-01-01 7.5343600000000000 2009-01-01 7.1017800000000010 2010-01-01 6.5930899999999990 2011-01-01 5.8712599999999995 2012-01-01 5.9815300000000000 2013-01-01 7.4950399999999995 2014-01-01 8.3528399999999990 2015-01-01 9.7935600000000010 2016-01-01 9.2766500000000000