Year	Percent
1960-01-01	17.67540000000000
1961-01-01	18.01380000000000
1962-01-01	18.97240000000000
1963-01-01	19.10670000000000
1964-01-01	18.49630000000000
1965-01-01	17.42080000000000
1966-01-01	16.98980000000000
1967-01-01	17.24440000000000
1968-01-01	17.91680000000000
1969-01-01	18.16700000000000
1970-01-01	14.91800000000000
1971-01-01	14.13800000000000
1972-01-01	14.44120000000000
1973-01-01	16.86050000000000
1974-01-01	19.08850000000000
1975-01-01	19.54110000000000
1976-01-01	20.92090000000000
1977-01-01	23.66910000000000
1978-01-01	26.53370000000000
1979-01-01	27.62990000000000
1980-01-01	32.82330000000000
1981-01-01	41.94790000000000
1982-01-01	49.86430000000000
1983-01-01	52.54380000000000
1984-01-01	57.35920000000000
1985-01-01	57.96430000000000
1986-01-01	66.72730000000000
1987-01-01	58.28440000000000
1988-01-01	60.63210000000000
1989-01-01	57.86860000000000
1990-01-01	58.24820000000000
1991-01-01	65.63840000000000
1992-01-01	62.34570000000000
1993-01-01	66.06680000000000
1994-01-01	64.63600000000001
1995-01-01	62.96910000000000
1996-01-01	60.81330000000000
1997-01-01	59.99750000000000
1998-01-01	58.46920000000000
1999-01-01	58.39250000000000
2000-01-01	58.14710000000000
2001-01-01	62.55070000000000
2002-01-01	67.13280000000000
2003-01-01	71.32810000000000
2004-01-01	75.31780000000000
2005-01-01	76.20270000000000
2006-01-01	74.65580000000000
2007-01-01	72.31720000000000
2008-01-01	72.33950000000000
2009-01-01	65.51860000000000
2010-01-01	62.17400000000000
2011-01-01	59.16540000000000
2012-01-01	54.87360000000000
2013-01-01	57.38750000000000
2014-01-01	58.51900000000000
2015-01-01	60.41860000000000
2016-01-01	69.51899999999999