Year	Percent
1960-01-01	11.1936000000000000
1961-01-01	10.8234000000000000
1962-01-01	8.7877500000000000
1963-01-01	7.9584600000000005
1964-01-01	7.1653600000000010
1965-01-01	10.4004000000000000
1966-01-01	10.3284000000000000
1967-01-01	9.0592899999999990
1968-01-01	10.1739000000000000
1969-01-01	10.8286000000000000
1970-01-01	12.2421000000000000
1971-01-01	13.9992000000000000
1972-01-01	15.4284000000000000
1973-01-01	17.5728000000000000
1974-01-01	19.7689000000000000
1975-01-01	21.5438000000000000
1976-01-01	21.3219000000000000
1977-01-01	21.2928000000000000
1978-01-01	22.2276000000000000
1979-01-01	19.7583000000000000
1980-01-01	18.9062000000000000
1981-01-01	19.6081000000000000
1982-01-01	19.9545000000000000
1983-01-01	19.6096000000000000
1984-01-01	18.2023000000000000
1985-01-01	17.5399000000000000
1986-01-01	21.0861000000000000
1987-01-01	22.3129000000000000
1988-01-01	20.1207000000000000
1989-01-01	20.5458000000000000
1990-01-01	18.5277000000000000
1991-01-01	13.1919000000000000
1992-01-01	14.7204000000000000
1993-01-01	16.4552000000000000
1994-01-01	16.9080000000000000
1995-01-01	16.8574000000000000
1996-01-01	17.7148000000000000
1997-01-01	19.0316000000000000
1998-01-01	19.5282000000000000
1999-01-01	21.1678000000000000
2000-01-01	22.5319000000000000
2001-01-01	20.6209000000000000
2002-01-01	16.7419000000000000
2003-01-01	18.1654000000000000
2004-01-01	18.5402000000000000
2005-01-01	16.4244000000000000
2006-01-01	17.0703000000000000
2007-01-01	17.5570000000000020
2008-01-01	17.8152000000000000
2009-01-01	18.0437000000000000
2010-01-01	18.6994000000000000
2011-01-01	19.6826000000000000
2012-01-01	20.0480000000000000
2013-01-01	20.7262000000000000
2014-01-01	20.7500000000000000
2015-01-01	20.8239000000000000
2016-01-01	21.5272000000000000