Year	Percent
1961-01-01	74.903200000000000
1962-01-01	72.772400000000000
1963-01-01	70.639000000000000
1964-01-01	70.591500000000000
1965-01-01	69.273600000000000
1966-01-01	68.477400000000000
1967-01-01	67.122600000000000
1968-01-01	66.454000000000000
1969-01-01	65.995400000000000
1970-01-01	62.591200000000000
1971-01-01	60.461900000000000
1972-01-01	63.217800000000000
1973-01-01	65.742700000000000
1974-01-01	73.839800000000000
1975-01-01	83.794000000000000
1976-01-01	88.976800000000000
1977-01-01	91.267500000000000
1978-01-01	91.267500000000000
1979-01-01	81.530900000000000
1980-01-01	69.756100000000000
1981-01-01	53.221300000000000
1982-01-01	44.686500000000000
1983-01-01	45.737100000000000
1984-01-01	45.737100000000000
1985-01-01	45.737100000000000
1986-01-01	43.486999999999995
1987-01-01	40.161700000000000
1988-01-01	36.819600000000000
1989-01-01	37.806800000000000
1990-01-01	41.361600000000000
1991-01-01	46.202200000000000
1992-01-01	51.727000000000000
1993-01-01	57.197600000000000
1994-01-01	54.775300000000000
1995-01-01	50.983200000000000
1996-01-01	50.888200000000000
1997-01-01	53.126900000000000
1998-01-01	55.041200000000000
1999-01-01	57.211500000000000
2000-01-01	68.099700000000000
2001-01-01	76.208900000000000
2002-01-01	76.524300000000000
2003-01-01	77.482100000000000
2004-01-01	82.363200000000000
2005-01-01	86.939800000000000
2006-01-01	90.064900000000000
2007-01-01	92.602600000000000
2008-01-01	94.289100000000000
2009-01-01	95.393999999999990
2010-01-01	95.219400000000000
2011-01-01	95.343600000000000
2012-01-01	96.074700000000000
2013-01-01	96.555400000000000
2014-01-01	97.157600000000000
2015-01-01	97.024100000000000
2016-01-01	96.684500000000000