Year Percent 1960-01-01 2.92902000000000000 1961-01-01 2.94545000000000000 1962-01-01 2.86615000000000000 1963-01-01 2.65465000000000000 1964-01-01 2.52543000000000000 1965-01-01 2.23752000000000000 1966-01-01 2.22032000000000000 1967-01-01 2.35290000000000000 1968-01-01 2.15715000000000000 1969-01-01 2.00318000000000000 1970-01-01 1.67754000000000030 1971-01-01 1.31869000000000000 1972-01-01 1.22621000000000000 1973-01-01 1.01780000000000000 1974-01-01 0.83905100000000000 1975-01-01 1.06785000000000000 1976-01-01 1.23518000000000000 1977-01-01 1.03417999999999990 1978-01-01 0.96276700000000000 1979-01-01 0.95945000000000000 1980-01-01 0.86380499999999990 1981-01-01 0.58782600000000010 1982-01-01 0.50944400000000000 1983-01-01 0.79192400000000000 1984-01-01 1.15909000000000000 1985-01-01 1.29067999999999980 1986-01-01 1.15110000000000000 1987-01-01 1.15448000000000000 1988-01-01 1.08590000000000000 1989-01-01 0.96473400000000000 1990-01-01 1.04366000000000000 1991-01-01 1.13487000000000000 1992-01-01 1.19446000000000000 1993-01-01 1.19878000000000000 1994-01-01 1.00485000000000000 1995-01-01 0.88117800000000000 1996-01-01 0.85812900000000010 1997-01-01 0.87163099999999990 1998-01-01 0.80943400000000000 1999-01-01 0.56315200000000010 2000-01-01 0.30701700000000000 2001-01-01 0.26108300000000000 2002-01-01 0.24258100000000000 2003-01-01 0.27491000000000000 2004-01-01 0.33116200000000000 2005-01-01 0.37032200000000000 2006-01-01 0.40518899999999997 2007-01-01 0.44702400000000000 2008-01-01 0.61945000000000000 2009-01-01 0.82894500000000000 2010-01-01 1.00777000000000000 2011-01-01 1.61185000000000000 2012-01-01 2.48515000000000000 2013-01-01 2.54767000000000000 2014-01-01 2.09816000000000000 2015-01-01 3.93390000000000000 2016-01-01 9.13053000000000000