Year	Percent
1979-01-01	12.95720822500000
1980-01-01	12.51039237500000
1981-01-01	11.39698347500000
1982-01-01	13.82590838333330
1983-01-01	18.28280067500000
1984-01-01	16.74631604166670
1985-01-01	15.13232179166670
1986-01-01	15.02552623333330
1987-01-01	14.91051019166670
1988-01-01	13.38384435833330
1989-01-01	11.13529940833330
1990-01-01	13.00438025833330
1991-01-01	17.46578266666670
1992-01-01	19.26580596666670
1993-01-01	18.51516653333330
1994-01-01	16.85290680000000
1995-01-01	15.18509660000000
1996-01-01	15.62621051666670
1997-01-01	15.82701260833330
1998-01-01	14.45180999166670
1999-01-01	13.10488204166670
2000-01-01	12.07916349166670
2001-01-01	13.47604389166670
2002-01-01	12.78559900000000
2003-01-01	11.95159687500000
2004-01-01	11.35999159166670
2005-01-01	10.60986773333330
2006-01-01	10.02015143333330
2007-01-01	9.35729292500000
2008-01-01	8.80414470833333
2009-01-01	11.45491990000000
2010-01-01	11.54108625000000
2011-01-01	11.35926146666670
2012-01-01	11.71553416666670
2013-01-01	12.20884795000000
2014-01-01	13.30109051666670
2015-01-01	13.09623085833330
2016-01-01	12.63550175833330
2017-01-01	12.59712292500000