Year	Percent
1976-01-01	1.9393599999999998
1977-01-01	8.1740500000000000
1978-01-01	13.1666000000000000
1979-01-01	14.4983000000000000
1980-01-01	23.4177000000000000
1981-01-01	36.4474000000000000
1982-01-01	45.5371000000000000
1983-01-01	50.8816000000000000
1984-01-01	55.6288000000000000
1985-01-01	54.5121000000000000
1986-01-01	50.0921000000000000
1987-01-01	48.2031000000000000
1988-01-01	50.0265000000000000
1989-01-01	54.3805000000000000
1990-01-01	56.0695000000000000
1991-01-01	50.6769000000000000
1992-01-01	42.9021000000000000
1993-01-01	39.2618000000000000
1994-01-01	38.8663000000000000
1995-01-01	41.1385000000000000
1996-01-01	44.6935000000000000
1997-01-01	50.6408000000000000
1998-01-01	56.3623000000000000
1999-01-01	57.1154000000000000
2000-01-01	54.5759000000000000
2001-01-01	54.5408000000000000
2002-01-01	56.7317000000000000
2003-01-01	59.1571000000000000
2004-01-01	74.6417000000000000
2005-01-01	76.1211000000000000
2006-01-01	81.5964000000000000
2007-01-01	86.8508000000000000
2008-01-01	86.1817000000000000
2009-01-01	83.6508000000000000
2010-01-01	83.6033000000000000
2011-01-01	84.8959000000000000
2012-01-01	83.0985000000000000
2013-01-01	78.6553000000000000
2014-01-01	77.1663000000000000
2015-01-01	78.9248000000000000
2016-01-01	78.9881000000000000