Year	Percent
1960-01-01	91.79270000000000
1961-01-01	91.01490000000000
1962-01-01	91.67170000000000
1963-01-01	93.62830000000000
1964-01-01	93.56560000000000
1965-01-01	93.46850000000000
1966-01-01	94.77640000000000
1967-01-01	96.49460000000000
1968-01-01	97.72000000000000
1969-01-01	98.29080000000000
1970-01-01	98.32110000000000
1971-01-01	97.82500000000000
1972-01-01	95.53550000000000
1973-01-01	93.30240000000000
1974-01-01	92.18240000000000
1975-01-01	87.13060000000000
1976-01-01	73.23510000000000
1977-01-01	67.33640000000000
1978-01-01	68.51480000000000
1979-01-01	58.27270000000000
1980-01-01	50.74190000000000
1981-01-01	51.32420000000000
1982-01-01	54.63520000000000
1983-01-01	54.62770000000000
1984-01-01	51.39440000000000
1985-01-01	52.88880000000000
1986-01-01	57.20330000000000
1987-01-01	65.31700000000000
1988-01-01	75.50890000000000
1989-01-01	77.76910000000000
1990-01-01	78.76450000000000
1991-01-01	82.58250000000000
1992-01-01	89.66420000000000
1993-01-01	88.18299999999999
1994-01-01	86.74380000000000
1995-01-01	85.11090000000000
1996-01-01	81.26890000000000
1997-01-01	74.98160000000000
1998-01-01	68.96010000000000
1999-01-01	68.45540000000000
2000-01-01	70.99010000000000
2001-01-01	74.51590000000000
2002-01-01	76.70060000000000
2003-01-01	76.73960000000000
2004-01-01	75.76800000000000
2005-01-01	77.02860000000000
2006-01-01	79.09740000000000
2007-01-01	82.13160000000000
2008-01-01	83.05430000000000
2009-01-01	80.02840000000000
2010-01-01	81.30199999999999
2011-01-01	84.62580000000000
2012-01-01	85.55440000000000
2013-01-01	85.62780000000000
2014-01-01	82.10400000000000
2015-01-01	81.26890000000000
2016-01-01	83.97840000000000