Year	Percent
1980-01-01	16.907100000000000
1981-01-01	16.974600000000000
1982-01-01	15.555000000000000
1983-01-01	16.512500000000000
1984-01-01	16.856200000000000
1985-01-01	17.855500000000000
1986-01-01	19.616600000000000
1987-01-01	19.058200000000000
1988-01-01	26.253200000000000
1989-01-01	23.779900000000000
1990-01-01	22.769100000000000
1991-01-01	21.046400000000000
1992-01-01	20.188100000000000
1993-01-01	20.538300000000000
1994-01-01	20.213000000000000
1995-01-01	19.866000000000000
1996-01-01	19.365000000000000
1997-01-01	18.610400000000000
1998-01-01	18.610400000000000
1999-01-01	16.890000000000000
2000-01-01	13.489000000000000
2001-01-01	11.274900000000000
2002-01-01	11.306400000000000
2003-01-01	11.625300000000000
2004-01-01	11.232800000000000
2005-01-01	11.123200000000000
2006-01-01	9.933670000000000
2007-01-01	9.065030000000000
2008-01-01	9.672340000000000
2009-01-01	9.945100000000000
2010-01-01	12.887200000000000
2011-01-01	12.748400000000000
2012-01-01	15.440000000000000
2013-01-01	15.466000000000000
2014-01-01	15.661400000000000
2015-01-01	15.017000000000001
2016-01-01	13.463600000000000