Year Percent 1970-01-01 4.33845000000000000 1971-01-01 4.68760000000000000 1972-01-01 3.35710000000000000 1973-01-01 2.58172000000000020 1974-01-01 1.52918000000000000 1975-01-01 1.70974000000000000 1976-01-01 1.43837000000000010 1977-01-01 1.66412999999999990 1978-01-01 1.49064000000000000 1979-01-01 1.25437999999999980 1980-01-01 0.95878500000000000 1981-01-01 1.00792000000000010 1982-01-01 1.12151000000000000 1983-01-01 0.80325600000000010 1984-01-01 0.61268300000000000 1985-01-01 0.54023400000000000 1986-01-01 0.56204200000000000 1987-01-01 0.72967299999999990 1988-01-01 0.64140500000000000 1989-01-01 0.62015200000000000 1990-01-01 0.56732900000000000 1991-01-01 2.82180999999999970 1992-01-01 2.89563000000000000 1993-01-01 2.28244000000000020 1994-01-01 3.27907000000000000 1995-01-01 2.68173000000000000 1996-01-01 1.87467000000000000 1997-01-01 2.20018000000000000 1998-01-01 2.19972999999999970 1999-01-01 1.62416000000000000 2000-01-01 1.44186000000000010 2001-01-01 1.22386000000000000 2002-01-01 1.88512000000000010 2003-01-01 2.57869000000000000 2004-01-01 2.88309000000000000 2005-01-01 0.16473200000000000 2006-01-01 0.16150100000000000 2007-01-01 0.07334900000000000 2008-01-01 0.06060300000000000 2009-01-01 0.10956600000000001 2010-01-01 0.12194800000000000 2011-01-01 0.10142500000000000 2012-01-01 0.10276600000000001 2013-01-01 0.09992700000000000 2014-01-01 0.14214400000000000 2015-01-01 0.16573100000000000 2016-01-01 0.17438399999999998 2017-01-01 1.22830000000000000