Year	Percent
1979-01-01	30.852900000000000
1980-01-01	31.180100000000000
1981-01-01	32.353800000000000
1982-01-01	33.907100000000000
1983-01-01	38.325400000000000
1984-01-01	33.984100000000000
1985-01-01	32.408100000000000
1986-01-01	30.820700000000000
1987-01-01	31.165500000000000
1988-01-01	33.700400000000000
1989-01-01	40.873900000000000
1990-01-01	41.835400000000000
1991-01-01	45.729800000000000
1992-01-01	49.500800000000000
1993-01-01	54.222600000000000
1994-01-01	54.258100000000000
1995-01-01	55.038300000000000
1996-01-01	54.026400000000000
1997-01-01	53.035200000000000
1998-01-01	54.703900000000000
1999-01-01	56.748000000000005
2000-01-01	57.444400000000000
2001-01-01	54.793900000000000
2002-01-01	51.411100000000000
2003-01-01	53.698300000000000
2004-01-01	52.982600000000000
2005-01-01	52.768000000000000
2006-01-01	50.082700000000000
2007-01-01	53.035700000000000
2008-01-01	55.085200000000000
2009-01-01	60.547400000000000
2010-01-01	63.736700000000000
2011-01-01	63.492500000000000
2012-01-01	66.127300000000000
2013-01-01	61.677400000000000
2014-01-01	58.087500000000000
2015-01-01	57.519500000000000
2016-01-01	57.424900000000000