Year	Percent
1960-01-01	65.03640000000000
1961-01-01	70.85110000000000
1962-01-01	82.68390000000000
1963-01-01	87.25540000000000
1964-01-01	90.02280000000000
1965-01-01	94.15500000000000
1966-01-01	96.20120000000000
1967-01-01	98.83990000000000
1968-01-01	96.97450000000000
1969-01-01	92.68040000000000
1970-01-01	93.82410000000000
1971-01-01	90.03820000000000
1972-01-01	87.18799999999999
1973-01-01	88.40230000000000
1974-01-01	89.29280000000000
1975-01-01	86.70340000000000
1976-01-01	80.08710000000000
1977-01-01	79.53170000000000
1978-01-01	77.56850000000000
1979-01-01	76.82660000000000
1980-01-01	78.73860000000000
1981-01-01	80.33880000000000
1982-01-01	80.52940000000000
1983-01-01	78.11040000000000
1984-01-01	82.86010000000000
1985-01-01	94.08420000000000
1986-01-01	100.48400000000000
1987-01-01	95.35870000000000
1988-01-01	92.52720000000000
1989-01-01	97.27730000000000
1990-01-01	99.19540000000000
1991-01-01	95.11300000000000
1992-01-01	86.03630000000000
1993-01-01	79.66950000000000
1994-01-01	75.13620000000000
1995-01-01	75.72310000000000
1996-01-01	75.55670000000000
1997-01-01	69.81960000000000
1998-01-01	68.83890000000000
1999-01-01	73.85040000000000
2000-01-01	79.00760000000000
2001-01-01	78.12010000000000
2002-01-01	71.14330000000000
2003-01-01	69.02840000000000
2004-01-01	74.76320000000000
2005-01-01	77.14110000000000
2006-01-01	77.79410000000000
2007-01-01	77.96240000000000
2008-01-01	81.35660000000000
2009-01-01	80.46660000000000
2010-01-01	71.51720000000000
2011-01-01	65.63650000000000
2012-01-01	58.12670000000000
2013-01-01	51.82230000000000
2014-01-01	49.33970000000000
2015-01-01	48.68260000000000
2016-01-01	48.16080000000000