Year	Percent
1960-01-01	12.225100000000000
1961-01-01	9.681939999999999
1962-01-01	8.735920000000000
1963-01-01	7.556060000000000
1964-01-01	6.674930000000001
1965-01-01	7.346460000000000
1966-01-01	7.157990000000000
1967-01-01	7.971730000000000
1968-01-01	9.320310000000001
1969-01-01	14.764500000000000
1970-01-01	20.403200000000000
1971-01-01	22.850100000000000
1972-01-01	26.065800000000000
1973-01-01	28.222700000000000
1974-01-01	29.431500000000000
1975-01-01	32.789700000000000
1976-01-01	32.448700000000000
1977-01-01	33.426600000000000
1978-01-01	33.253600000000000
1979-01-01	38.702500000000000
1980-01-01	25.847400000000000
1981-01-01	25.752600000000000
1982-01-01	26.913600000000000
1983-01-01	27.539600000000000
1984-01-01	24.596500000000000
1985-01-01	22.236900000000000
1986-01-01	16.158300000000000
1987-01-01	10.270999999999999
1988-01-01	23.964400000000000
1989-01-01	40.878100000000000
1990-01-01	30.885300000000000
1991-01-01	21.478600000000000
1992-01-01	27.502400000000000
1993-01-01	36.777800000000000
1994-01-01	41.760800000000000
1995-01-01	39.816400000000000
1996-01-01	40.134200000000000
1997-01-01	40.123800000000000
1998-01-01	35.510200000000000
1999-01-01	29.663000000000000
2000-01-01	30.208000000000002
2001-01-01	29.841700000000000
2002-01-01	28.035800000000000
2003-01-01	27.884700000000000
2004-01-01	26.806800000000000
2005-01-01	28.530700000000000
2006-01-01	33.804100000000000
2007-01-01	40.894000000000000
2008-01-01	46.485900000000000
2009-01-01	53.078100000000000
2010-01-01	55.408500000000000
2011-01-01	60.069400000000000
2012-01-01	63.960400000000000
2013-01-01	66.339400000000000
2014-01-01	68.054700000000000
2015-01-01	70.177400000000000
2016-01-01	67.826800000000000