Year Percent 1980-01-01 0.20770400000000000 1981-01-01 0.22008699999999998 1982-01-01 0.47198700000000000 1983-01-01 0.81492600000000000 1984-01-01 0.73559300000000000 1985-01-01 0.72217000000000000 1986-01-01 1.08697000000000000 1987-01-01 1.22753000000000000 1988-01-01 1.18062999999999980 1989-01-01 0.92131800000000010 1990-01-01 1.19397999999999980 1991-01-01 1.16093999999999990 1992-01-01 1.31857000000000000 1993-01-01 1.09522000000000000 1994-01-01 1.78005000000000000 1995-01-01 1.60805000000000000 1996-01-01 3.77043000000000000 1997-01-01 6.22173000000000000 1998-01-01 11.84930000000000000 1999-01-01 7.26336000000000050 2000-01-01 5.53533000000000000 2001-01-01 4.63914000000000000 2002-01-01 3.77318000000000040 2003-01-01 3.36595000000000000 2004-01-01 3.30083000000000040 2005-01-01 3.84899999999999980 2006-01-01 4.14885000000000000 2007-01-01 3.80119000000000000 2008-01-01 3.74098000000000040 2009-01-01 5.42606999999999900 2010-01-01 4.67365000000000000 2011-01-01 4.49607000000000000 2012-01-01 5.52654000000000000 2013-01-01 6.50038000000000100 2014-01-01 7.35278000000000000 2015-01-01 10.06360000000000000 2016-01-01 10.61890000000000000