Year	Percent
1970-01-01	9.804170000000000
1971-01-01	9.684289999999999
1972-01-01	10.468200000000000
1973-01-01	9.910180000000000
1974-01-01	11.079800000000000
1975-01-01	12.042900000000000
1976-01-01	11.708000000000000
1977-01-01	12.729200000000000
1978-01-01	13.450999999999999
1979-01-01	12.939300000000000
1980-01-01	16.080000000000000
1981-01-01	21.892800000000000
1982-01-01	27.765100000000000
1983-01-01	25.671600000000000
1984-01-01	20.698400000000000
1985-01-01	21.403600000000000
1986-01-01	24.656100000000000
1987-01-01	28.449300000000000
1988-01-01	30.809000000000000
1989-01-01	30.820700000000000
1990-01-01	29.137900000000000
1991-01-01	29.961300000000000
1992-01-01	28.189400000000000
1993-01-01	25.041400000000000
1994-01-01	35.837600000000000
1995-01-01	26.475900000000000
1996-01-01	28.735700000000000
1997-01-01	28.767100000000000
1998-01-01	28.164200000000000
1999-01-01	30.955600000000000
2000-01-01	33.735000000000000
2001-01-01	33.112400000000000
2002-01-01	33.561200000000000
2003-01-01	34.461000000000000
2004-01-01	37.551000000000000
2005-01-01	34.815300000000000
2006-01-01	37.079000000000000
2007-01-01	34.895800000000000
2008-01-01	30.261500000000000
2009-01-01	32.764700000000000
2010-01-01	36.914200000000000
2011-01-01	33.644700000000000
2012-01-01	30.541999999999998
2013-01-01	32.895800000000000
2014-01-01	33.487300000000000
2015-01-01	33.854000000000000
2016-01-01	35.147400000000000