Year	Percent
1961-01-01	96.22180000000000
1962-01-01	96.42030000000000
1963-01-01	96.32880000000000
1964-01-01	93.29870000000000
1965-01-01	91.68560000000000
1966-01-01	91.09560000000000
1967-01-01	90.09899999999999
1968-01-01	90.08890000000000
1969-01-01	91.19980000000000
1970-01-01	89.08950000000000
1971-01-01	89.35799999999999
1972-01-01	89.19410000000000
1973-01-01	85.75140000000000
1974-01-01	84.97290000000000
1975-01-01	83.00010000000000
1976-01-01	81.77290000000000
1977-01-01	81.46850000000000
1978-01-01	76.70110000000000
1979-01-01	76.88710000000000
1980-01-01	77.99630000000000
1981-01-01	83.60250000000000
1982-01-01	82.91130000000000
1983-01-01	81.47000000000000
1984-01-01	81.10050000000000
1985-01-01	84.15690000000000
1986-01-01	80.23710000000000
1987-01-01	78.42200000000000
1988-01-01	78.17140000000000
1989-01-01	77.69700000000000
1990-01-01	77.43360000000000
1991-01-01	77.80250000000000
1992-01-01	74.88600000000001
1993-01-01	66.56570000000000
1994-01-01	58.33510000000000
1995-01-01	60.76680000000000
1996-01-01	60.92410000000000
1997-01-01	58.76120000000000
1998-01-01	56.44010000000000
1999-01-01	58.75420000000000
2000-01-01	57.45220000000000
2001-01-01	47.39690000000000
2002-01-01	38.19210000000000
2003-01-01	33.79800000000000
2004-01-01	34.31810000000000
2005-01-01	34.65290000000000
2006-01-01	37.06850000000000
2007-01-01	39.45390000000000
2008-01-01	59.94880000000000
2009-01-01	84.62500000000000
2010-01-01	83.26830000000000
2011-01-01	91.57830000000000
2012-01-01	96.94630000000000
2013-01-01	97.85140000000000
2014-01-01	83.02960000000000
2015-01-01	70.46180000000000