Year	Percent
1960-01-01	33.7775
1961-01-01	33.2781
1962-01-01	34.9468
1963-01-01	37.2635
1964-01-01	38.2413
1965-01-01	39.8522
1966-01-01	42.5726
1967-01-01	47.8563
1968-01-01	49.5462
1969-01-01	48.5437
1970-01-01	40.8687
1971-01-01	41.4268
1972-01-01	43.1868
1973-01-01	43.4322
1974-01-01	43.7125
1975-01-01	45.8444
1976-01-01	46.2512
1977-01-01	47.3668
1978-01-01	48.6519
1979-01-01	48.2208
1980-01-01	47.4006
1981-01-01	47.3947
1982-01-01	47.8142
1983-01-01	48.3487
1984-01-01	48.5114
1985-01-01	49.4648
1986-01-01	49.7542
1987-01-01	50.9983
1988-01-01	50.4454
1989-01-01	49.5551
1990-01-01	50.8125
1991-01-01	64.4719
1992-01-01	52.2045
1993-01-01	55.6659
1994-01-01	56.4133
1995-01-01	56.0108
1996-01-01	58.5405
1997-01-01	60.3621
1998-01-01	61.4333
1999-01-01	78.4142
2000-01-01	90.9159
2001-01-01	59.4289
2002-01-01	60.3744
2003-01-01	62.2941
2004-01-01	62.4188
2005-01-01	63.3881
2006-01-01	64.0072
2007-01-01	65.3457
2008-01-01	69.8405
2009-01-01	74.7120
2010-01-01	72.5596
2011-01-01	72.9765
2012-01-01	75.7629
2013-01-01	77.5100
2014-01-01	78.1735
2015-01-01	79.6367
2016-01-01	81.1122