Year	Percent
1960-01-01	11.310000000000000
1961-01-01	12.569500000000000
1962-01-01	14.627700000000000
1963-01-01	15.548000000000000
1964-01-01	17.795700000000000
1965-01-01	17.750300000000000
1966-01-01	17.866500000000000
1967-01-01	18.403400000000000
1968-01-01	18.816800000000000
1969-01-01	18.433200000000000
1970-01-01	16.029900000000000
1971-01-01	15.948500000000000
1972-01-01	16.802000000000000
1973-01-01	17.433100000000000
1974-01-01	18.037200000000000
1975-01-01	19.279000000000000
1976-01-01	20.527200000000000
1977-01-01	21.090800000000000
1978-01-01	22.307500000000000
1979-01-01	23.562100000000000
1980-01-01	26.005500000000000
1981-01-01	27.202700000000000
1982-01-01	28.553100000000000
1983-01-01	28.007400000000000
1984-01-01	24.300700000000000
1985-01-01	19.440900000000000
1986-01-01	15.134700000000000
1987-01-01	13.137100000000000
1988-01-01	13.757200000000000
1989-01-01	14.107000000000001
1990-01-01	14.974600000000000
1991-01-01	15.867600000000000
1992-01-01	16.737900000000000
1993-01-01	20.327000000000000
1994-01-01	24.021000000000000
1995-01-01	28.790800000000000
1996-01-01	37.242600000000000
1997-01-01	45.298000000000000
1998-01-01	45.655500000000000
1999-01-01	39.211200000000000
2000-01-01	35.703400000000000
2001-01-01	33.676800000000000
2002-01-01	30.982500000000000
2003-01-01	28.862100000000000
2004-01-01	26.945900000000000
2005-01-01	25.162300000000000
2006-01-01	23.440500000000000
2007-01-01	22.421700000000000
2008-01-01	25.184100000000000
2009-01-01	28.650000000000000
2010-01-01	27.787800000000000
2011-01-01	29.873300000000000
2012-01-01	31.479700000000000
2013-01-01	33.122700000000000
2014-01-01	36.140300000000000
2015-01-01	39.422300000000000
2016-01-01	41.409700000000000