Year	Percent
1960-01-01	15.401000000000000
1961-01-01	15.323900000000000
1962-01-01	18.329200000000000
1963-01-01	19.426500000000000
1964-01-01	21.428900000000000
1965-01-01	19.576600000000000
1966-01-01	20.568300000000000
1967-01-01	21.614500000000000
1968-01-01	21.376800000000000
1969-01-01	22.295300000000000
1970-01-01	17.344000000000000
1971-01-01	17.334300000000000
1972-01-01	17.221500000000000
1973-01-01	19.498400000000000
1974-01-01	22.252100000000000
1975-01-01	23.998600000000000
1976-01-01	25.201700000000000
1977-01-01	25.026999999999997
1978-01-01	25.949500000000000
1979-01-01	26.585800000000000
1980-01-01	26.329000000000000
1981-01-01	26.919300000000000
1982-01-01	27.539400000000000
1983-01-01	27.539400000000000
1984-01-01	27.539400000000000
1985-01-01	27.539400000000000
1986-01-01	27.539400000000000
1987-01-01	32.794200000000000
1988-01-01	34.114600000000000
1989-01-01	36.953000000000000
1990-01-01	36.507200000000000
1991-01-01	34.875100000000000
1992-01-01	32.311200000000000
1993-01-01	32.666500000000000
1994-01-01	32.935000000000000
1995-01-01	32.975300000000000
1996-01-01	32.164400000000000
1997-01-01	33.962900000000000
1998-01-01	35.086500000000000
1999-01-01	35.690900000000000
2000-01-01	38.550300000000000
2001-01-01	40.068800000000000
2002-01-01	41.732800000000000
2003-01-01	40.894300000000000
2004-01-01	41.004300000000000
2005-01-01	41.770000000000000
2006-01-01	42.696800000000000
2007-01-01	43.778500000000000
2008-01-01	45.345500000000000
2009-01-01	48.233999999999995
2010-01-01	50.919700000000000
2011-01-01	53.931400000000000
2012-01-01	53.652700000000000
2013-01-01	54.611800000000000
2014-01-01	54.130800000000000
2015-01-01	54.952800000000000
2016-01-01	54.496000000000000