Year	Percent
1960-01-01	25.210200000000000
1961-01-01	25.613700000000000
1962-01-01	26.834600000000000
1963-01-01	27.525400000000000
1964-01-01	28.163200000000000
1965-01-01	26.428900000000000
1966-01-01	20.838700000000000
1967-01-01	19.012600000000000
1968-01-01	17.026500000000000
1969-01-01	16.481300000000000
1970-01-01	17.965900000000000
1971-01-01	18.595600000000000
1972-01-01	18.634500000000000
1973-01-01	16.737000000000002
1974-01-01	14.206200000000000
1975-01-01	13.134800000000000
1976-01-01	16.660300000000000
1977-01-01	21.182500000000000
1978-01-01	24.400200000000000
1979-01-01	24.957200000000000
1980-01-01	28.393200000000000
1981-01-01	33.806100000000000
1982-01-01	45.926900000000000
1983-01-01	48.695200000000000
1984-01-01	42.636200000000000
1985-01-01	39.397600000000000
1986-01-01	36.921100000000000
1987-01-01	34.316800000000000
1988-01-01	35.152600000000000
1989-01-01	38.453500000000000
1990-01-01	36.658400000000000
1991-01-01	34.642700000000000
1992-01-01	33.014700000000000
1993-01-01	30.863000000000003
1994-01-01	28.082600000000000
1995-01-01	28.697600000000000
1996-01-01	28.828200000000000
1997-01-01	30.283900000000000
1998-01-01	32.648600000000000
1999-01-01	37.835400000000000
2000-01-01	41.487400000000000
2001-01-01	45.536700000000000
2002-01-01	52.051200000000000
2003-01-01	51.867500000000000
2004-01-01	46.495900000000000
2005-01-01	42.922900000000000
2006-01-01	41.594300000000000
2007-01-01	39.086100000000000
2008-01-01	39.460800000000000
2009-01-01	39.602200000000000
2010-01-01	38.505600000000000
2011-01-01	40.393700000000000
2012-01-01	40.924400000000000
2013-01-01	41.661600000000000
2014-01-01	44.205100000000000
2015-01-01	49.062300000000000
2016-01-01	51.572300000000000