Year	Percent
1960-01-01	54.7625
1961-01-01	55.4992
1962-01-01	56.6207
1963-01-01	58.5164
1964-01-01	59.3650
1965-01-01	59.7865
1966-01-01	58.4347
1967-01-01	59.2699
1968-01-01	59.6521
1969-01-01	57.6494
1970-01-01	57.7600
1971-01-01	60.0668
1972-01-01	62.4802
1973-01-01	62.9660
1974-01-01	63.6749
1975-01-01	63.1945
1976-01-01	62.6722
1977-01-01	63.3655
1978-01-01	62.4247
1979-01-01	61.7857
1980-01-01	63.0631
1981-01-01	62.6447
1982-01-01	66.8308
1983-01-01	66.6372
1984-01-01	66.5751
1985-01-01	68.1122
1986-01-01	69.8861
1987-01-01	70.8073
1988-01-01	68.8859
1989-01-01	67.9856
1990-01-01	66.7514
1991-01-01	65.4702
1992-01-01	61.9504
1993-01-01	58.7492
1994-01-01	55.1220
1995-01-01	54.3745
1996-01-01	55.2756
1997-01-01	56.0829
1998-01-01	57.7850
1999-01-01	59.3458
2000-01-01	60.7741
2001-01-01	63.8252
2002-01-01	65.1148
2003-01-01	64.8537
2004-01-01	63.8883
2005-01-01	64.1716
2006-01-01	66.4031
2007-01-01	70.4946
2008-01-01	77.8720
2009-01-01	83.2097
2010-01-01	80.5757
2011-01-01	79.3782
2012-01-01	80.2137
2013-01-01	80.9765
2014-01-01	81.3575
2015-01-01	80.9590
2016-01-01	81.3141