Year	Percent
1960-01-01	28.246600000000000
1961-01-01	28.453100000000000
1962-01-01	32.112900000000000
1963-01-01	31.097600000000000
1964-01-01	33.489300000000000
1965-01-01	30.578200000000000
1966-01-01	32.315900000000000
1967-01-01	33.926900000000000
1968-01-01	33.234800000000000
1969-01-01	34.185400000000000
1970-01-01	25.969300000000000
1971-01-01	25.452800000000000
1972-01-01	25.384400000000000
1973-01-01	28.981100000000000
1974-01-01	33.299400000000000
1975-01-01	36.252700000000000
1976-01-01	38.345400000000000
1977-01-01	38.331800000000000
1978-01-01	39.666400000000000
1979-01-01	39.889400000000000
1980-01-01	38.501100000000000
1981-01-01	39.406900000000000
1982-01-01	41.446000000000005
1983-01-01	41.446000000000005
1984-01-01	41.446000000000005
1985-01-01	41.446000000000005
1986-01-01	41.446000000000005
1987-01-01	42.530300000000000
1988-01-01	43.419600000000000
1989-01-01	45.799300000000000
1990-01-01	45.236100000000000
1991-01-01	43.966700000000000
1992-01-01	42.075800000000000
1993-01-01	43.235600000000000
1994-01-01	43.069800000000000
1995-01-01	43.181400000000000
1996-01-01	42.353700000000000
1997-01-01	43.867600000000000
1998-01-01	44.926400000000000
1999-01-01	46.201000000000000
2000-01-01	49.457700000000000
2001-01-01	50.855600000000000
2002-01-01	53.125600000000000
2003-01-01	52.001400000000000
2004-01-01	51.508100000000000
2005-01-01	52.199000000000000
2006-01-01	53.372600000000000
2007-01-01	54.391300000000000
2008-01-01	55.980300000000000
2009-01-01	59.464600000000000
2010-01-01	62.786000000000000
2011-01-01	67.732500000000000
2012-01-01	67.530900000000000
2013-01-01	67.800400000000000
2014-01-01	67.543200000000000
2015-01-01	69.214900000000000
2016-01-01	68.920300000000000