Year	Percent
1967-01-01	93.5299
1968-01-01	93.7713
1969-01-01	94.1221
1970-01-01	95.6710
1971-01-01	98.0564
1972-01-01	97.8527
1973-01-01	95.8197
1974-01-01	92.3499
1975-01-01	84.1962
1976-01-01	71.5629
1977-01-01	64.2375
1978-01-01	73.0625
1979-01-01	88.5795
1980-01-01	92.5499
1981-01-01	91.7416
1982-01-01	83.7994
1983-01-01	68.6557
1984-01-01	55.5425
1985-01-01	47.2755
1986-01-01	40.4733
1987-01-01	34.4550
1988-01-01	30.4391
1989-01-01	30.5516
1990-01-01	34.5259
1991-01-01	38.6840
1992-01-01	40.6831
1993-01-01	42.3873
1994-01-01	42.6141
1995-01-01	71.4138
1996-01-01	85.1231
1997-01-01	89.6687
1998-01-01	78.2457
1999-01-01	62.7009
2000-01-01	43.9678
2001-01-01	51.4219
2002-01-01	69.1020
2003-01-01	67.6091
2004-01-01	72.4776
2005-01-01	76.3857
2006-01-01	80.8303
2007-01-01	86.3092
2008-01-01	91.2478
2009-01-01	86.6797
2010-01-01	84.8206
2011-01-01	87.8899
2012-01-01	89.7446
2013-01-01	86.4404
2014-01-01	86.7238
2015-01-01	81.2850
2016-01-01	75.3056