Year	Percent
1960-01-01	47.48080000000000
1961-01-01	45.30270000000000
1962-01-01	43.22560000000000
1963-01-01	42.00740000000000
1964-01-01	41.52960000000000
1965-01-01	46.65180000000000
1966-01-01	51.28640000000000
1967-01-01	55.83690000000000
1968-01-01	58.53490000000000
1969-01-01	68.46270000000000
1970-01-01	76.21790000000000
1971-01-01	79.92870000000000
1972-01-01	80.30300000000000
1973-01-01	80.90450000000000
1974-01-01	82.23350000000000
1975-01-01	82.20060000000000
1976-01-01	81.26650000000000
1977-01-01	80.07440000000000
1978-01-01	77.63360000000000
1979-01-01	77.71690000000000
1980-01-01	76.97010000000000
1981-01-01	78.41070000000000
1982-01-01	82.11680000000000
1983-01-01	84.32080000000000
1984-01-01	85.69260000000000
1985-01-01	84.02450000000000
1986-01-01	73.26240000000000
1987-01-01	65.44890000000000
1988-01-01	68.53420000000000
1989-01-01	71.02420000000000
1990-01-01	65.02860000000000
1991-01-01	54.39130000000000
1992-01-01	60.84930000000000
1993-01-01	69.97060000000000
1994-01-01	80.65450000000000
1995-01-01	89.47070000000000
1996-01-01	93.03660000000000
1997-01-01	93.52340000000000
1998-01-01	85.82590000000000
1999-01-01	82.25520000000000
2000-01-01	84.93799999999999
2001-01-01	83.14670000000000
2002-01-01	78.64420000000000
2003-01-01	77.83050000000000
2004-01-01	79.81400000000000
2005-01-01	82.46620000000000
2006-01-01	85.00180000000000
2007-01-01	85.62790000000000
2008-01-01	84.55140000000000
2009-01-01	82.42930000000000
2010-01-01	82.29670000000000
2011-01-01	83.85090000000000
2012-01-01	84.30840000000000
2013-01-01	84.38120000000000
2014-01-01	84.24660000000000
2015-01-01	83.58960000000000
2016-01-01	82.41830000000000