Year	Percent
1976-01-01	95.69160000000000
1977-01-01	94.03910000000000
1978-01-01	91.63720000000000
1979-01-01	87.67830000000000
1980-01-01	87.97430000000000
1981-01-01	79.08740000000000
1982-01-01	79.83110000000000
1983-01-01	79.76260000000000
1984-01-01	76.70410000000000
1985-01-01	72.14970000000000
1986-01-01	75.84660000000000
1987-01-01	84.85460000000000
1988-01-01	90.65550000000000
1989-01-01	93.00220000000000
1990-01-01	95.91650000000000
1991-01-01	96.41150000000000
1992-01-01	93.86330000000000
1993-01-01	90.37360000000000
1994-01-01	87.35380000000000
1995-01-01	86.53110000000000
1996-01-01	84.07799999999999
1997-01-01	84.78660000000000
1998-01-01	87.40770000000000
1999-01-01	89.60730000000000
2000-01-01	92.02010000000000
2001-01-01	92.13190000000000
2002-01-01	92.77760000000000
2003-01-01	89.89910000000000
2004-01-01	87.38650000000000
2005-01-01	87.82670000000000
2006-01-01	86.66910000000000
2007-01-01	86.63270000000000
2008-01-01	88.42310000000000
2009-01-01	90.44510000000000
2010-01-01	91.86230000000000
2011-01-01	91.47480000000000
2012-01-01	91.09450000000000
2013-01-01	91.59080000000000
2014-01-01	91.97870000000000
2015-01-01	90.41540000000000
2016-01-01	86.62730000000000