Year	Percent
1971-01-01	0.502524000000000
1972-01-01	2.446770000000000
1973-01-01	2.730050000000000
1974-01-01	2.702350000000000
1975-01-01	3.553200000000000
1976-01-01	4.527320000000000
1977-01-01	5.938910000000000
1978-01-01	9.139240000000000
1979-01-01	8.822810000000000
1980-01-01	7.104400000000000
1981-01-01	7.781190000000000
1982-01-01	8.413440000000000
1983-01-01	9.107289999999999
1984-01-01	9.515100000000000
1985-01-01	10.872000000000000
1986-01-01	11.500700000000000
1987-01-01	15.065100000000000
1988-01-01	14.377200000000000
1989-01-01	14.691200000000000
1990-01-01	17.515100000000000
1991-01-01	23.335300000000000
1992-01-01	35.183900000000000
1993-01-01	45.537700000000000
1994-01-01	49.396300000000000
1995-01-01	37.756500000000000
1996-01-01	37.630000000000000
1997-01-01	34.692800000000000
1998-01-01	31.126700000000000
1999-01-01	29.237000000000000
2000-01-01	27.317200000000000
2001-01-01	27.771700000000000
2002-01-01	29.326500000000000
2003-01-01	35.288200000000000
2004-01-01	35.209500000000000
2005-01-01	31.469000000000000
2006-01-01	32.302600000000000
2007-01-01	26.019600000000000
2008-01-01	21.136100000000000
2009-01-01	30.678100000000000
2010-01-01	34.372900000000000
2011-01-01	35.222200000000000
2012-01-01	44.847300000000000
2013-01-01	49.547700000000000
2014-01-01	50.116400000000000
2015-01-01	60.065900000000000
2016-01-01	60.485800000000000