Year Percent 1980-01-01 0.0115730000000000000 1981-01-01 0.0142420000000000000 1982-01-01 0.0120959999999999990 1983-01-01 0.0117060000000000000 1984-01-01 0.0111349999999999990 1985-01-01 0.0061000000000000000 1986-01-01 0.0019410000000000000 1987-01-01 0.0075980000000000010 1988-01-01 0.0062759999999999995 1989-01-01 0.0058710000000000000 1990-01-01 0.0054200000000000000 1991-01-01 0.0053549999999999995 1992-01-01 0.0376870000000000000 1993-01-01 0.1026450000000000000 1994-01-01 0.1292680000000000000 1995-01-01 0.1530369999999999800 1996-01-01 0.1408800000000000000 1997-01-01 0.1414180000000000200 1998-01-01 0.1593380000000000000 1999-01-01 0.1209720000000000000 2000-01-01 0.1088570000000000000 2001-01-01 0.3491200000000000000 2002-01-01 0.3481090000000000000 2003-01-01 0.3345490000000000000 2004-01-01 0.3176870000000000000 2005-01-01 0.2838280000000000000 2006-01-01 0.3195150000000000000 2007-01-01 0.3254559999999999700 2008-01-01 0.3053960000000000000 2009-01-01 0.3485120000000000000 2010-01-01 0.5921520000000000000 2011-01-01 0.5412110000000000000 2012-01-01 0.3968560000000000000 2013-01-01 0.4085030000000000000 2014-01-01 0.3299250000000000000 2015-01-01 0.3329970000000000000 2016-01-01 0.3069090000000000000