Year	Percent
1960-01-01	61.312600000000000
1961-01-01	58.654100000000000
1962-01-01	58.964500000000000
1963-01-01	59.601100000000000
1964-01-01	57.625300000000000
1965-01-01	55.945400000000000
1966-01-01	55.859100000000000
1967-01-01	57.209300000000000
1968-01-01	60.083200000000000
1969-01-01	59.781100000000000
1970-01-01	56.347900000000000
1971-01-01	56.189700000000000
1972-01-01	56.940900000000000
1973-01-01	57.900500000000000
1974-01-01	57.435800000000000
1975-01-01	53.911200000000000
1976-01-01	52.184800000000000
1977-01-01	51.498999999999995
1978-01-01	52.240100000000000
1979-01-01	53.942700000000000
1980-01-01	52.917300000000000
1981-01-01	54.856500000000000
1982-01-01	55.032100000000000
1983-01-01	52.510200000000000
1984-01-01	50.172700000000000
1985-01-01	48.989700000000000
1986-01-01	48.415000000000000
1987-01-01	48.940000000000000
1988-01-01	48.010400000000000
1989-01-01	47.342700000000000
1990-01-01	46.276400000000000
1991-01-01	43.949100000000000
1992-01-01	44.592900000000000
1993-01-01	44.029400000000000
1994-01-01	41.789300000000000
1995-01-01	39.495400000000000
1996-01-01	40.658400000000000
1997-01-01	40.751100000000000
1998-01-01	38.743600000000000
1999-01-01	38.351400000000000
2000-01-01	37.803700000000000
2001-01-01	40.672400000000000
2002-01-01	43.685800000000000
2003-01-01	43.726200000000000
2004-01-01	42.930200000000000
2005-01-01	44.378900000000000
2006-01-01	46.683800000000000
2007-01-01	48.816700000000000
2008-01-01	53.285400000000000
2009-01-01	60.772600000000000
2010-01-01	61.352700000000000
2011-01-01	62.457700000000000
2012-01-01	64.928200000000000
2013-01-01	65.687100000000000
2014-01-01	65.361700000000000
2015-01-01	64.652600000000000
2016-01-01	66.462600000000000