Year	Percent
1960-01-01	67.83750000000000
1961-01-01	75.13460000000000
1962-01-01	79.29470000000000
1963-01-01	81.07110000000000
1964-01-01	84.87450000000000
1965-01-01	85.99840000000000
1966-01-01	88.13220000000000
1967-01-01	90.63470000000000
1968-01-01	89.89710000000000
1969-01-01	84.19570000000000
1970-01-01	79.37330000000000
1971-01-01	78.50950000000000
1972-01-01	79.37770000000000
1973-01-01	81.27320000000000
1974-01-01	85.44270000000000
1975-01-01	89.31670000000000
1976-01-01	89.93540000000000
1977-01-01	89.30350000000000
1978-01-01	88.58350000000000
1979-01-01	87.83990000000000
1980-01-01	86.41530000000000
1981-01-01	85.30810000000000
1982-01-01	85.05480000000000
1983-01-01	85.45020000000000
1984-01-01	87.23330000000000
1985-01-01	88.29890000000000
1986-01-01	89.08020000000000
1987-01-01	90.95250000000000
1988-01-01	94.47180000000000
1989-01-01	97.46590000000000
1990-01-01	97.84070000000000
1991-01-01	97.90410000000000
1992-01-01	98.24730000000000
1993-01-01	98.66680000000000
1994-01-01	99.30510000000000
1995-01-01	99.60300000000000
1996-01-01	99.55510000000000
1997-01-01	99.21530000000000
1998-01-01	98.06480000000000
1999-01-01	97.23030000000000
2000-01-01	97.57260000000000
2001-01-01	97.59830000000000
2002-01-01	97.72220000000000
2003-01-01	98.09100000000001
2004-01-01	98.30560000000000
2005-01-01	98.54470000000000
2006-01-01	98.48370000000000
2007-01-01	97.94390000000000
2008-01-01	97.39700000000000
2009-01-01	97.15190000000000
2010-01-01	97.20680000000000
2011-01-01	97.60620000000000
2012-01-01	98.00760000000000
2013-01-01	98.32530000000000
2014-01-01	98.58550000000000
2015-01-01	98.62440000000000
2016-01-01	98.47140000000000