Year	Percent
1960-01-01	59.59430000000000
1961-01-01	60.26460000000000
1962-01-01	61.02500000000000
1963-01-01	62.94580000000000
1964-01-01	63.97790000000000
1965-01-01	64.27760000000000
1966-01-01	62.72500000000000
1967-01-01	63.49420000000000
1968-01-01	63.79760000000000
1969-01-01	61.79580000000000
1970-01-01	62.03850000000000
1971-01-01	64.31900000000000
1972-01-01	66.58950000000000
1973-01-01	66.90020000000000
1974-01-01	67.60780000000000
1975-01-01	67.29420000000000
1976-01-01	66.61930000000000
1977-01-01	67.08510000000000
1978-01-01	66.14830000000000
1979-01-01	65.53399999999999
1980-01-01	66.80180000000000
1981-01-01	66.10580000000000
1982-01-01	70.34520000000000
1983-01-01	70.17360000000000
1984-01-01	70.07050000000000
1985-01-01	71.63910000000000
1986-01-01	73.48310000000000
1987-01-01	74.48630000000000
1988-01-01	72.56720000000000
1989-01-01	71.64530000000000
1990-01-01	70.51790000000000
1991-01-01	69.48890000000000
1992-01-01	66.08280000000000
1993-01-01	63.03520000000000
1994-01-01	59.56280000000000
1995-01-01	58.96180000000000
1996-01-01	59.89850000000000
1997-01-01	60.74500000000000
1998-01-01	62.54760000000000
1999-01-01	64.48380000000000
2000-01-01	66.10580000000000
2001-01-01	64.87320000000000
2002-01-01	62.29020000000000
2003-01-01	62.74390000000000
2004-01-01	62.76150000000000
2005-01-01	63.66090000000000
2006-01-01	65.80199999999999
2007-01-01	68.51720000000000
2008-01-01	73.42699999999999
2009-01-01	73.54080000000000
2010-01-01	68.24390000000000
2011-01-01	68.43220000000000
2012-01-01	70.00530000000000
2013-01-01	71.18850000000000
2014-01-01	71.81130000000000
2015-01-01	71.95090000000000
2016-01-01	73.53550000000000