Year	Percent
1962-01-01	18.834000000000000
1963-01-01	16.600200000000000
1964-01-01	17.408100000000000
1965-01-01	20.877400000000000
1966-01-01	20.486200000000000
1967-01-01	20.677600000000000
1968-01-01	20.030300000000000
1969-01-01	22.413000000000000
1970-01-01	22.556200000000000
1971-01-01	23.547800000000000
1972-01-01	23.922700000000000
1973-01-01	23.862400000000000
1974-01-01	26.211700000000000
1975-01-01	26.802100000000000
1976-01-01	26.983800000000000
1977-01-01	32.067000000000000
1978-01-01	33.435900000000000
1979-01-01	31.867500000000000
1980-01-01	28.179800000000000
1981-01-01	27.743300000000000
1982-01-01	27.454900000000000
1983-01-01	26.940100000000000
1984-01-01	25.942100000000000
1985-01-01	28.116300000000000
1986-01-01	30.357200000000000
1987-01-01	31.403400000000000
1988-01-01	31.307000000000000
1989-01-01	29.221100000000000
1990-01-01	28.986900000000000
1991-01-01	28.650000000000000
1992-01-01	29.044800000000000
1993-01-01	26.805900000000000
1994-01-01	23.644800000000000
1995-01-01	24.905300000000000
1996-01-01	23.675600000000000
1997-01-01	22.890300000000000
1998-01-01	22.810400000000000
1999-01-01	22.497200000000000
2000-01-01	22.076999999999998
2001-01-01	21.554800000000000
2002-01-01	24.601999999999997
2003-01-01	23.675500000000000
2004-01-01	21.209500000000000
2005-01-01	22.469600000000000
2006-01-01	23.759100000000000
2007-01-01	26.624500000000000
2008-01-01	27.521400000000000
2009-01-01	28.383600000000000
2010-01-01	30.896400000000000
2011-01-01	36.445300000000000
2012-01-01	34.602500000000000
2013-01-01	33.695900000000000
2014-01-01	33.863000000000000
2015-01-01	35.976800000000000
2016-01-01	36.625400000000000