Year	Percent
1960-01-01	7.082540000000000
1961-01-01	6.949350000000000
1962-01-01	7.277350000000000
1963-01-01	7.518120000000000
1964-01-01	8.602160000000001
1965-01-01	9.544440000000000
1966-01-01	10.221700000000000
1967-01-01	11.350900000000000
1968-01-01	11.692500000000000
1969-01-01	12.247500000000000
1970-01-01	13.644100000000000
1971-01-01	14.762300000000000
1972-01-01	16.858400000000000
1973-01-01	17.902200000000000
1974-01-01	16.415700000000000
1975-01-01	17.105200000000000
1976-01-01	18.503800000000000
1977-01-01	18.263200000000000
1978-01-01	19.113300000000000
1979-01-01	18.426500000000000
1980-01-01	17.514800000000000
1981-01-01	18.580100000000000
1982-01-01	20.867100000000000
1983-01-01	21.799700000000000
1984-01-01	21.057300000000000
1985-01-01	21.693500000000000
1986-01-01	20.448100000000000
1987-01-01	19.921900000000000
1988-01-01	19.573700000000000
1989-01-01	19.426200000000000
1990-01-01	16.048400000000000
1991-01-01	16.251600000000000
1992-01-01	19.146300000000000
1993-01-01	18.021400000000000
1994-01-01	15.935700000000000
1995-01-01	14.956900000000000
1996-01-01	15.141900000000000
1997-01-01	15.646500000000000
1998-01-01	16.831500000000000
1999-01-01	16.956100000000000
2000-01-01	18.046800000000000
2001-01-01	20.877000000000000
2002-01-01	22.452700000000000
2003-01-01	28.168800000000000
2004-01-01	33.446900000000000
2005-01-01	34.830000000000000
2006-01-01	35.455999999999996
2007-01-01	34.606300000000000
2008-01-01	34.702000000000000
2009-01-01	36.299100000000000
2010-01-01	37.653200000000000
2011-01-01	36.928000000000004
2012-01-01	37.456700000000000
2013-01-01	38.694700000000000
2014-01-01	39.236400000000000
2015-01-01	39.195200000000000
2016-01-01	39.535100000000000