Year Percent 1980-01-01 1.3160200000000000 1981-01-01 1.1803600000000000 1982-01-01 1.2147800000000000 1983-01-01 1.1856100000000000 1984-01-01 1.2399200000000001 1985-01-01 1.4154200000000001 1986-01-01 1.5221500000000000 1987-01-01 1.3357400000000000 1988-01-01 0.9509139999999999 1989-01-01 0.6021090000000000 1990-01-01 0.5253580000000000 1991-01-01 0.5494010000000000 1992-01-01 0.1328540000000000 1993-01-01 1.7836100000000000 1994-01-01 3.1714200000000000 1995-01-01 3.7060100000000000 1996-01-01 6.3216300000000000 1997-01-01 9.5418899999999990 1998-01-01 12.1759000000000000 1999-01-01 11.4549000000000000 2000-01-01 11.0470000000000000 2001-01-01 11.0369000000000000 2002-01-01 11.8961000000000000 2003-01-01 12.6700000000000000 2004-01-01 10.7022000000000000 2005-01-01 8.9712600000000010 2006-01-01 8.0872700000000000 2007-01-01 6.3139000000000000 2008-01-01 5.2173600000000000 2009-01-01 6.5410300000000000 2010-01-01 6.4235400000000000 2011-01-01 6.1980400000000000 2012-01-01 6.1396100000000000 2013-01-01 6.5560500000000000 2014-01-01 6.4749300000000005 2015-01-01 6.9426300000000000 2016-01-01 6.3745800000000000