Year Percent 1980-01-01 0.013078999999999999 1981-01-01 0.012764000000000000 1982-01-01 0.043396000000000000 1983-01-01 0.065457000000000000 1984-01-01 0.086172000000000000 1985-01-01 0.354779000000000000 1986-01-01 0.872462000000000100 1987-01-01 1.588070000000000000 1988-01-01 1.617720000000000000 1989-01-01 1.400650000000000000 1990-01-01 1.406370000000000100 1991-01-01 1.442460000000000000 1992-01-01 1.357179999999999800 1993-01-01 2.090030000000000000 1994-01-01 2.419530000000000000 1995-01-01 1.847260000000000000 1996-01-01 1.695520000000000100 1997-01-01 1.863870000000000100 1998-01-01 1.750560000000000000 1999-01-01 1.671120000000000200 2000-01-01 1.505100000000000000 2001-01-01 1.381070000000000000 2002-01-01 1.259460000000000000 2003-01-01 1.292730000000000000 2004-01-01 1.297930000000000000 2005-01-01 1.217380000000000000 2006-01-01 1.075490000000000000 2007-01-01 1.159400000000000000 2008-01-01 1.012260000000000000 2009-01-01 0.932944000000000000 2010-01-01 1.191420000000000100 2011-01-01 1.570550000000000000 2012-01-01 2.046670000000000000 2013-01-01 2.876610000000000000 2014-01-01 4.139920000000000000 2015-01-01 4.782890000000000000 2016-01-01 5.714480000000000000