Year Percent 1982-01-01 0.301000000000000000 1983-01-01 0.234951000000000020 1984-01-01 0.155032000000000000 1985-01-01 0.087564000000000000 1986-01-01 0.148053000000000000 1987-01-01 0.083539000000000000 1988-01-01 0.104478000000000000 1989-01-01 0.054305999999999990 1990-01-01 0.054298000000000000 1991-01-01 0.101682000000000010 1992-01-01 0.145083000000000000 1993-01-01 0.141969000000000000 1994-01-01 0.151863000000000000 1995-01-01 0.047648000000000000 1996-01-01 0.193575000000000000 1997-01-01 0.477222999999999950 1998-01-01 0.033429000000000000 1999-01-01 0.048445999999999996 2000-01-01 0.062582000000000000 2001-01-01 0.090265000000000000 2002-01-01 0.160013000000000020 2003-01-01 0.278586000000000000 2004-01-01 0.339644000000000000 2005-01-01 0.145980000000000000 2006-01-01 0.156951000000000000 2007-01-01 0.192364000000000000 2008-01-01 0.198698000000000000 2009-01-01 0.180226000000000000 2010-01-01 0.223519000000000000 2011-01-01 0.218795000000000000 2012-01-01 0.199352000000000000 2013-01-01 0.185174000000000000 2014-01-01 0.285341000000000000 2015-01-01 0.401687000000000000 2016-01-01 0.314767000000000000 2017-01-01 0.234244000000000000