Year	Percent
1961-01-01	57.431500000000000
1962-01-01	53.992000000000000
1963-01-01	44.476400000000000
1964-01-01	36.797700000000000
1965-01-01	38.463700000000000
1966-01-01	42.202900000000000
1967-01-01	41.307900000000000
1968-01-01	46.108000000000004
1969-01-01	44.198400000000000
1970-01-01	45.002200000000000
1971-01-01	49.135300000000000
1972-01-01	52.895500000000000
1973-01-01	61.207300000000000
1974-01-01	69.996500000000000
1975-01-01	66.850500000000000
1976-01-01	66.546900000000000
1977-01-01	71.530600000000000
1978-01-01	68.918700000000000
1979-01-01	68.960800000000000
1980-01-01	71.941100000000000
1981-01-01	75.495700000000000
1982-01-01	76.961200000000000
1983-01-01	74.935600000000000
1984-01-01	76.219600000000000
1985-01-01	80.258700000000000
1986-01-01	77.102700000000000
1987-01-01	73.305500000000000
1988-01-01	68.538500000000000
1989-01-01	70.430700000000000
1990-01-01	76.434000000000000
1991-01-01	76.880400000000000
1992-01-01	76.128900000000000
1993-01-01	76.911600000000000
1994-01-01	81.688900000000000
1995-01-01	83.322300000000000
1996-01-01	84.447100000000000
1997-01-01	85.024500000000000
1998-01-01	82.797999999999990
1999-01-01	78.363000000000000
2000-01-01	80.811200000000000
2001-01-01	86.068500000000000
2002-01-01	84.757400000000000
2003-01-01	80.182300000000000
2004-01-01	79.874900000000000
2005-01-01	85.576800000000000
2006-01-01	88.794200000000000
2007-01-01	85.699500000000000
2008-01-01	90.400000000000000
2009-01-01	96.606500000000000
2010-01-01	93.432700000000000
2011-01-01	96.708100000000000
2012-01-01	99.557999999999990
2013-01-01	93.438600000000000
2014-01-01	90.332900000000000
2015-01-01	92.148000000000000
2016-01-01	95.764000000000000