Year Percent 1979-01-01 9.884770000000000 1980-01-01 12.098200000000000 1981-01-01 17.963300000000000 1982-01-01 33.672300000000000 1983-01-01 27.193200000000000 1984-01-01 11.357999999999999 1985-01-01 18.200600000000000 1986-01-01 26.172200000000000 1987-01-01 30.146600000000000 1988-01-01 20.768700000000000 1989-01-01 14.310000000000000 1990-01-01 15.464600000000000 1991-01-01 18.154900000000000 1992-01-01 32.209900000000000 1993-01-01 57.690900000000000 1994-01-01 54.945400000000000 1995-01-01 34.762400000000000 1996-01-01 32.290000000000000 1997-01-01 34.892900000000000 1998-01-01 35.479500000000000 1999-01-01 43.493600000000000 2000-01-01 50.148500000000000 2001-01-01 46.920600000000000 2002-01-01 39.411700000000000 2003-01-01 45.202700000000000 2004-01-01 60.366100000000000 2005-01-01 74.978600000000000 2006-01-01 93.361400000000000 2007-01-01 114.219000000000000 2008-01-01 88.578600000000000 2009-01-01 68.865600000000000 2010-01-01 90.713800000000000 2011-01-01 76.040300000000000 2012-01-01 59.945500000000000 2013-01-01 64.368800000000000 2014-01-01 65.662700000000000 2015-01-01 71.549700000000000 2016-01-01 72.405500000000000 2017-01-01 65.463200000000000