Year	Percent
1970-01-01	9.550660000000000
1971-01-01	9.430050000000000
1972-01-01	10.196200000000000
1973-01-01	9.652230000000000
1974-01-01	10.795800000000000
1975-01-01	11.732900000000000
1976-01-01	11.405999999999999
1977-01-01	12.421400000000000
1978-01-01	13.145600000000000
1979-01-01	12.726300000000000
1980-01-01	14.588200000000000
1981-01-01	18.299800000000000
1982-01-01	23.760300000000000
1983-01-01	22.063400000000000
1984-01-01	17.504700000000000
1985-01-01	18.038400000000000
1986-01-01	20.993100000000000
1987-01-01	24.627200000000000
1988-01-01	26.983800000000000
1989-01-01	27.129800000000000
1990-01-01	25.905600000000000
1991-01-01	26.763100000000000
1992-01-01	25.260300000000000
1993-01-01	22.415100000000000
1994-01-01	31.673000000000002
1995-01-01	23.220700000000000
1996-01-01	25.278600000000000
1997-01-01	25.013100000000000
1998-01-01	24.505600000000000
1999-01-01	27.363400000000000
2000-01-01	30.105100000000000
2001-01-01	29.850300000000000
2002-01-01	30.314800000000000
2003-01-01	31.217300000000000
2004-01-01	34.068300000000000
2005-01-01	31.444800000000000
2006-01-01	33.463600000000000
2007-01-01	35.391800000000000
2008-01-01	34.199800000000000
2009-01-01	37.200400000000000
2010-01-01	41.928600000000000
2011-01-01	38.089800000000000
2012-01-01	34.675100000000000
2013-01-01	36.970200000000000
2014-01-01	38.346000000000000
2015-01-01	39.661500000000000
2016-01-01	41.044900000000000