Year	Percent
1962-01-01	18.602400000000000
1963-01-01	18.916800000000000
1964-01-01	18.640800000000000
1965-01-01	19.487100000000000
1966-01-01	19.158000000000000
1967-01-01	20.225600000000000
1968-01-01	20.897500000000000
1969-01-01	21.315900000000000
1970-01-01	15.283600000000000
1971-01-01	15.645000000000000
1972-01-01	16.560300000000000
1973-01-01	16.961000000000000
1974-01-01	16.212000000000000
1975-01-01	15.873900000000000
1976-01-01	17.141500000000000
1977-01-01	18.370400000000000
1978-01-01	19.819200000000000
1979-01-01	18.214000000000002
1980-01-01	17.880100000000000
1981-01-01	19.765400000000000
1982-01-01	18.603200000000000
1983-01-01	14.747800000000000
1984-01-01	16.457600000000000
1985-01-01	20.200100000000000
1986-01-01	21.214800000000000
1987-01-01	19.997900000000000
1988-01-01	20.337400000000000
1989-01-01	21.296500000000000
1990-01-01	19.736900000000000
1991-01-01	18.659200000000000
1992-01-01	20.449100000000000
1993-01-01	21.854700000000000
1994-01-01	22.616000000000000
1995-01-01	20.495000000000000
1996-01-01	20.183200000000000
1997-01-01	22.189200000000000
1998-01-01	23.393600000000000
1999-01-01	23.587200000000000
2000-01-01	24.823800000000000
2001-01-01	23.112900000000000
2002-01-01	24.898100000000000
2003-01-01	22.171600000000000
2004-01-01	21.788200000000000
2005-01-01	19.811300000000000
2006-01-01	19.201300000000000
2007-01-01	20.520700000000000
2008-01-01	20.499500000000000
2009-01-01	22.063700000000000
2010-01-01	22.385300000000000
2011-01-01	23.296300000000000
2012-01-01	23.801800000000000
2013-01-01	23.361700000000000
2014-01-01	22.875400000000000
2015-01-01	23.534600000000000
2016-01-01	20.812800000000000