Year	Percent
1960-01-01	13.671400000000000
1961-01-01	13.121300000000000
1962-01-01	11.851100000000000
1963-01-01	11.335999999999999
1964-01-01	11.666500000000000
1965-01-01	14.647800000000000
1966-01-01	18.389500000000000
1967-01-01	19.203400000000000
1968-01-01	17.852900000000000
1969-01-01	17.604900000000000
1970-01-01	19.662500000000000
1971-01-01	20.415700000000000
1972-01-01	21.615700000000000
1973-01-01	27.543200000000000
1974-01-01	35.475700000000000
1975-01-01	36.153300000000000
1976-01-01	33.561300000000000
1977-01-01	31.731800000000000
1978-01-01	30.949800000000000
1979-01-01	31.700700000000000
1980-01-01	30.071600000000000
1981-01-01	27.869600000000000
1982-01-01	27.564800000000000
1983-01-01	26.194800000000000
1984-01-01	25.139100000000000
1985-01-01	25.285400000000000
1986-01-01	24.359800000000000
1987-01-01	22.996200000000000
1988-01-01	24.472100000000000
1989-01-01	28.240400000000000
1990-01-01	31.753200000000000
1991-01-01	33.803300000000000
1992-01-01	33.246500000000000
1993-01-01	33.518500000000000
1994-01-01	34.782400000000000
1995-01-01	38.327000000000000
1996-01-01	42.455800000000000
1997-01-01	49.067200000000000
1998-01-01	52.965300000000000
1999-01-01	51.027600000000000
2000-01-01	49.642200000000000
2001-01-01	47.392700000000000
2002-01-01	46.090800000000000
2003-01-01	47.298200000000000
2004-01-01	47.067800000000000
2005-01-01	48.706300000000000
2006-01-01	50.086100000000000
2007-01-01	47.169500000000000
2008-01-01	44.392200000000000
2009-01-01	43.040100000000000
2010-01-01	41.812900000000000
2011-01-01	42.588600000000000
2012-01-01	46.906500000000000
2013-01-01	53.106000000000000
2014-01-01	58.211400000000000
2015-01-01	58.375700000000000
2016-01-01	59.013800000000000