Year	Percent
1966-01-01	90.64590000000000
1967-01-01	93.16970000000000
1968-01-01	96.99780000000000
1969-01-01	92.76290000000000
1970-01-01	84.01770000000000
1971-01-01	77.62060000000000
1972-01-01	77.56000000000000
1973-01-01	82.36740000000000
1974-01-01	82.17230000000000
1975-01-01	80.27260000000000
1976-01-01	80.82530000000000
1977-01-01	83.33620000000000
1978-01-01	81.02870000000000
1979-01-01	73.58500000000000
1980-01-01	69.60610000000000
1981-01-01	69.45370000000000
1982-01-01	70.27520000000000
1983-01-01	69.92270000000000
1984-01-01	67.69740000000000
1985-01-01	59.31550000000000
1986-01-01	49.44850000000000
1987-01-01	54.95560000000000
1988-01-01	60.37610000000000
1989-01-01	67.51650000000000
1990-01-01	62.75390000000000
1991-01-01	58.63020000000000
1992-01-01	58.19450000000000
1993-01-01	54.96540000000000
1994-01-01	57.40640000000000
1995-01-01	58.45370000000000
1996-01-01	56.85530000000000
1997-01-01	59.05270000000000
1998-01-01	65.94930000000000
1999-01-01	69.02250000000000
2000-01-01	69.64030000000000
2001-01-01	71.75399999999999
2002-01-01	76.91410000000000
2003-01-01	82.32640000000000
2004-01-01	83.47260000000000
2005-01-01	82.53850000000000
2006-01-01	82.16140000000000
2007-01-01	84.98440000000000
2008-01-01	87.91350000000000
2009-01-01	86.32040000000000
2010-01-01	85.72830000000000
2011-01-01	87.33880000000000
2012-01-01	87.00320000000000
2013-01-01	86.61200000000001
2014-01-01	86.78870000000000
2015-01-01	86.25110000000000
2016-01-01	86.19660000000000