Year Percent 1979-01-01 2.39389000000000030 1980-01-01 2.19475000000000000 1981-01-01 1.81735000000000000 1982-01-01 2.18893000000000000 1983-01-01 2.94050999999999970 1984-01-01 4.17847000000000000 1985-01-01 5.56350000000000000 1986-01-01 5.01835999999999950 1987-01-01 4.37373000000000000 1988-01-01 3.51990000000000000 1989-01-01 2.69059000000000030 1990-01-01 2.32901000000000000 1991-01-01 2.67567000000000000 1992-01-01 1.83208000000000000 1993-01-01 1.23941000000000010 1994-01-01 0.91914699999999990 1995-01-01 0.60949500000000000 1996-01-01 0.51018999999999990 1997-01-01 0.39716999999999997 1998-01-01 0.29541200000000000 1999-01-01 0.26213000000000003 2000-01-01 0.35683600000000000 2001-01-01 0.45676500000000000 2002-01-01 0.50591000000000010 2003-01-01 0.45149100000000000 2004-01-01 0.42236899999999994 2005-01-01 0.49320800000000000 2006-01-01 0.44649600000000000 2007-01-01 0.47360399999999997 2008-01-01 0.46289700000000000 2009-01-01 0.89164400000000010 2010-01-01 1.29619000000000000 2011-01-01 1.26080000000000000 2012-01-01 0.77017500000000000 2013-01-01 0.18015599999999998 2014-01-01 0.16784900000000000 2015-01-01 0.16101300000000002 2016-01-01 0.07884900000000000