Year Percent 1960-01-01 3.35836000000000000 1961-01-01 3.92875000000000000 1962-01-01 4.54724000000000000 1963-01-01 4.28566000000000000 1964-01-01 3.67220999999999980 1965-01-01 3.25060000000000000 1966-01-01 3.07323000000000000 1967-01-01 3.09222000000000000 1968-01-01 2.77700999999999980 1969-01-01 2.44888000000000000 1970-01-01 1.93017000000000020 1971-01-01 1.75483000000000000 1972-01-01 1.53918000000000000 1973-01-01 1.44241000000000000 1974-01-01 1.41087000000000000 1975-01-01 1.58338000000000000 1976-01-01 1.48430000000000000 1977-01-01 1.17198000000000000 1978-01-01 1.22036000000000010 1979-01-01 1.18110000000000000 1980-01-01 1.18175000000000000 1981-01-01 1.32326000000000000 1982-01-01 1.29792000000000000 1983-01-01 1.26331000000000000 1984-01-01 1.22592000000000010 1985-01-01 1.08955000000000000 1986-01-01 1.07806000000000000 1987-01-01 1.09480000000000000 1988-01-01 1.01310000000000000 1989-01-01 0.97536700000000000 1990-01-01 0.91047400000000000 1991-01-01 1.06674000000000000 1992-01-01 0.91213099999999990 1993-01-01 0.90411800000000000 1994-01-01 0.76347100000000000 1995-01-01 0.69341100000000000 1996-01-01 0.64900700000000000 1997-01-01 0.63028100000000010 1998-01-01 0.61618100000000010 1999-01-01 0.42396600000000000 2000-01-01 0.21652800000000003 2001-01-01 0.20204600000000000 2002-01-01 0.20105200000000000 2003-01-01 0.19988699999999998 2004-01-01 0.19544000000000000 2005-01-01 0.19235700000000000 2006-01-01 0.18525100000000000 2007-01-01 0.17646300000000000 2008-01-01 0.17392800000000000 2009-01-01 0.17992400000000000 2010-01-01 0.17167200000000000 2011-01-01 0.16459500000000000 2012-01-01 0.16130000000000000 2013-01-01 0.16078299999999998 2014-01-01 0.15875100000000000 2015-01-01 1.53793999999999990 2016-01-01 5.22321999999999950