Year Percent 1974-01-01 0.166682000000000000 1975-01-01 0.189865000000000000 1976-01-01 0.219133000000000000 1977-01-01 0.197497000000000000 1978-01-01 0.850579999999999900 1979-01-01 0.883957000000000000 1980-01-01 0.215644999999999980 1981-01-01 0.270575000000000000 1982-01-01 0.320829000000000000 1983-01-01 0.321319000000000000 1984-01-01 0.279465000000000000 1985-01-01 0.352648000000000000 1986-01-01 0.692319999999999900 1987-01-01 0.549172999999999900 1988-01-01 0.199847000000000000 1989-01-01 0.183728000000000000 1990-01-01 0.200370000000000000 1991-01-01 0.229819000000000000 1992-01-01 0.229406000000000000 1993-01-01 0.194237000000000000 1994-01-01 0.504811000000000000 1995-01-01 0.608047999999999900 1996-01-01 0.299651000000000000 1997-01-01 0.149449000000000000 1998-01-01 0.126489000000000020 1999-01-01 0.124910000000000000 2000-01-01 0.133460000000000000 2001-01-01 0.117710000000000000 2002-01-01 0.273604000000000000 2003-01-01 0.488008000000000000 2004-01-01 0.568260000000000000 2005-01-01 0.542638000000000100 2006-01-01 0.408936000000000000 2007-01-01 0.202992000000000000 2008-01-01 0.060547000000000004 2009-01-01 0.035862000000000000 2010-01-01 0.051998000000000000 2011-01-01 1.075650000000000000 2012-01-01 1.122850000000000000 2013-01-01 0.176001000000000000 2014-01-01 0.103948000000000000 2015-01-01 0.045675000000000000 2016-01-01 1.032850000000000000