Year	Percent
1970-01-01	8.791700000000000
1971-01-01	7.685260000000000
1972-01-01	8.097480000000001
1973-01-01	8.068820000000000
1974-01-01	8.091790000000000
1975-01-01	10.044400000000000
1976-01-01	11.897000000000000
1977-01-01	14.555400000000000
1978-01-01	19.204500000000000
1979-01-01	16.447100000000000
1980-01-01	13.082300000000000
1981-01-01	14.474000000000000
1982-01-01	21.521800000000000
1983-01-01	29.292900000000000
1984-01-01	33.487500000000000
1985-01-01	38.606600000000000
1986-01-01	47.397500000000000
1987-01-01	50.873999999999995
1988-01-01	52.169000000000000
1989-01-01	49.852900000000000
1990-01-01	41.690400000000000
1991-01-01	40.922500000000000
1992-01-01	42.074700000000000
1993-01-01	45.120200000000000
1994-01-01	45.509700000000000
1995-01-01	45.247600000000000
1996-01-01	42.333700000000000
1997-01-01	42.848100000000000
1998-01-01	50.677500000000000
1999-01-01	48.047000000000000
2000-01-01	43.259300000000000
2001-01-01	46.685000000000000
2002-01-01	50.075900000000000
2003-01-01	49.084700000000000
2004-01-01	46.284900000000000
2005-01-01	41.850200000000000
2006-01-01	42.746000000000000
2007-01-01	46.274400000000000
2008-01-01	44.886400000000000
2009-01-01	61.252800000000000
2010-01-01	54.093200000000000
2011-01-01	46.729800000000000
2012-01-01	48.391300000000000
2013-01-01	53.640800000000000
2014-01-01	58.362500000000000
2015-01-01	72.184800000000000
2016-01-01	75.401800000000000