Year	Percent
1960-01-01	23.066700000000000
1961-01-01	23.007700000000000
1962-01-01	24.043700000000000
1963-01-01	26.543000000000003
1964-01-01	28.531300000000000
1965-01-01	28.079500000000000
1966-01-01	27.368200000000000
1967-01-01	26.164900000000000
1968-01-01	24.154500000000000
1969-01-01	23.976600000000000
1970-01-01	13.626200000000000
1971-01-01	14.255200000000000
1972-01-01	14.271700000000000
1973-01-01	13.776800000000000
1974-01-01	12.616000000000000
1975-01-01	12.248800000000000
1976-01-01	13.616500000000000
1977-01-01	17.560400000000000
1978-01-01	20.655900000000000
1979-01-01	22.124800000000000
1980-01-01	23.480100000000000
1981-01-01	23.391900000000000
1982-01-01	24.474400000000000
1983-01-01	24.681300000000000
1984-01-01	23.398700000000000
1985-01-01	24.423700000000000
1986-01-01	24.561200000000000
1987-01-01	24.153800000000000
1988-01-01	24.952400000000000
1989-01-01	23.796500000000000
1990-01-01	21.970700000000000
1991-01-01	22.580500000000000
1992-01-01	23.551600000000000
1993-01-01	24.031000000000000
1994-01-01	25.492300000000000
1995-01-01	28.221500000000000
1996-01-01	30.499800000000000
1997-01-01	28.748700000000000
1998-01-01	29.371500000000000
1999-01-01	30.877100000000000
2000-01-01	30.352800000000000
2001-01-01	31.635400000000000
2002-01-01	31.506000000000000
2003-01-01	31.858300000000000
2004-01-01	32.082500000000000
2005-01-01	33.287700000000000
2006-01-01	33.033500000000000
2007-01-01	31.724700000000000
2008-01-01	30.487400000000000
2009-01-01	29.869900000000000
2010-01-01	30.265800000000000
2011-01-01	31.869300000000000
2012-01-01	31.269800000000000
2013-01-01	33.356900000000000
2014-01-01	34.963700000000000
2015-01-01	37.994900000000000
2016-01-01	46.580700000000000