Year	Percent
1960-01-01	8.432530000000000
1961-01-01	7.876500000000000
1962-01-01	8.182120000000000
1963-01-01	8.293700000000000
1964-01-01	8.661940000000000
1965-01-01	10.304600000000000
1966-01-01	12.270100000000000
1967-01-01	12.822600000000000
1968-01-01	12.960400000000000
1969-01-01	15.128300000000000
1970-01-01	11.957500000000000
1971-01-01	12.908200000000000
1972-01-01	14.555400000000000
1973-01-01	15.397600000000000
1974-01-01	14.067600000000000
1975-01-01	14.618300000000000
1976-01-01	16.594600000000000
1977-01-01	18.639200000000000
1978-01-01	24.412400000000000
1979-01-01	23.186200000000000
1980-01-01	20.249100000000000
1981-01-01	22.031999999999996
1982-01-01	23.103200000000000
1983-01-01	29.320500000000000
1984-01-01	32.506300000000000
1985-01-01	33.193600000000000
1986-01-01	34.121600000000000
1987-01-01	35.450500000000000
1988-01-01	34.687000000000000
1989-01-01	32.903900000000000
1990-01-01	29.728500000000000
1991-01-01	30.963400000000000
1992-01-01	33.362800000000000
1993-01-01	31.609900000000000
1994-01-01	26.656999999999996
1995-01-01	25.901800000000000
1996-01-01	26.641300000000000
1997-01-01	29.889400000000000
1998-01-01	33.333200000000000
1999-01-01	32.397700000000000
2000-01-01	29.575300000000000
2001-01-01	30.143600000000000
2002-01-01	30.719400000000000
2003-01-01	25.157900000000000
2004-01-01	23.782800000000000
2005-01-01	24.657100000000000
2006-01-01	26.693500000000000
2007-01-01	26.894800000000000
2008-01-01	24.091900000000000
2009-01-01	35.580200000000000
2010-01-01	31.166999999999998
2011-01-01	26.893800000000000
2012-01-01	28.556900000000000
2013-01-01	28.504200000000000
2014-01-01	30.114900000000000
2015-01-01	35.766400000000000
2016-01-01	40.320600000000000