Year	Percent
1975-01-01	10.334600000000000
1976-01-01	10.063100000000000
1977-01-01	10.352900000000000
1978-01-01	10.825700000000000
1979-01-01	9.826700000000000
1980-01-01	8.077880000000000
1981-01-01	7.595330000000001
1982-01-01	8.246700000000000
1983-01-01	9.662220000000000
1984-01-01	10.589900000000000
1985-01-01	17.439200000000000
1986-01-01	23.981900000000000
1987-01-01	20.570999999999998
1988-01-01	17.016400000000000
1989-01-01	21.545500000000000
1990-01-01	22.199700000000000
1991-01-01	23.690200000000000
1992-01-01	17.149500000000000
1993-01-01	18.349100000000000
1994-01-01	21.633800000000000
1995-01-01	22.120200000000000
1996-01-01	24.313100000000000
1997-01-01	31.686999999999998
1998-01-01	42.572700000000000
1999-01-01	56.322800000000000
2000-01-01	64.207000000000000
2001-01-01	59.127200000000000
2002-01-01	43.680800000000000
2003-01-01	37.900000000000000
2004-01-01	42.213500000000000
2005-01-01	41.778400000000000
2006-01-01	47.348300000000000
2007-01-01	56.431800000000000
2008-01-01	45.060900000000000
2009-01-01	34.196500000000000
2010-01-01	38.830100000000000
2011-01-01	35.831900000000000
2012-01-01	36.421700000000000
2013-01-01	46.198000000000000
2014-01-01	47.226600000000000
2015-01-01	46.954200000000000
2016-01-01	49.052800000000000
2017-01-01	54.262900000000000