Year Percent 1990-01-01 0.7143950000000000 1991-01-01 0.6619970000000001 1992-01-01 0.6645310000000001 1993-01-01 0.6732300000000000 1994-01-01 0.6862500000000000 1995-01-01 0.7061010000000000 1996-01-01 0.7934590000000000 1997-01-01 0.7406520000000001 1998-01-01 0.6985150000000000 1999-01-01 0.7018430000000000 2000-01-01 0.6849810000000001 2001-01-01 0.6655160000000000 2002-01-01 0.7089710000000000 2003-01-01 0.7426290000000000 2004-01-01 0.8148440000000000 2005-01-01 0.9136590000000000 2006-01-01 0.8823970000000000 2007-01-01 0.8713690000000001 2008-01-01 0.7835180000000000 2009-01-01 0.6938110000000000 2010-01-01 0.6263420000000000 2011-01-01 0.7171950000000000 2012-01-01 0.6019040000000000 2013-01-01 0.5573300000000000 2014-01-01 0.5318970000000001 2015-01-01 0.5258250000000000