Year	Percent
1980-01-01	3.2109400000000003
1981-01-01	3.3833200000000000
1982-01-01	3.4362500000000000
1983-01-01	3.9238199999999996
1984-01-01	5.0148600000000000
1985-01-01	5.7668599999999990
1986-01-01	6.6460700000000000
1987-01-01	6.4808500000000000
1988-01-01	6.0733300000000000
1989-01-01	5.1101300000000010
1990-01-01	8.0863900000000000
1991-01-01	3.7283100000000000
1992-01-01	33.9207000000000000
1993-01-01	37.2813000000000000
1994-01-01	27.8107000000000000
1995-01-01	30.8117000000000000
1996-01-01	30.3643000000000000
1997-01-01	32.5799000000000000
1998-01-01	35.7655000000000000
1999-01-01	37.6778000000000000
2000-01-01	27.4193000000000000
2001-01-01	36.2275000000000000
2002-01-01	35.1901000000000000
2003-01-01	31.3168000000000000
2004-01-01	27.7272000000000000
2005-01-01	23.8456000000000000
2006-01-01	23.3902000000000000
2007-01-01	21.2087000000000000
2008-01-01	17.6362000000000000
2009-01-01	23.5573000000000000
2010-01-01	21.9333000000000000
2011-01-01	21.8279000000000000
2012-01-01	21.9777000000000000
2013-01-01	23.3478000000000000
2014-01-01	27.9527000000000000
2015-01-01	33.4244000000000000
2016-01-01	37.7271000000000000