Year	Percent
1960-01-01	85.18913159
1961-01-01	86.58536585
1962-01-01	87.24637681
1963-01-01	87.04545455
1964-01-01	87.58791891
1965-01-01	89.03714389
1966-01-01	90.67796610
1967-01-01	90.12345679
1968-01-01	83.77153219
1969-01-01	82.99421718
1970-01-01	84.40218491
1971-01-01	83.53963647
1972-01-01	85.41376912
1973-01-01	88.51947879
1974-01-01	94.04502679
1975-01-01	97.74193548
1976-01-01	93.47181009
1977-01-01	95.24179992
1978-01-01	96.26103873
1979-01-01	95.27458493
1980-01-01	98.88037008
1981-01-01	102.41268070
1982-01-01	101.73195650
1983-01-01	99.93209597
1984-01-01	98.30469971
1985-01-01	96.36416404
1986-01-01	100.39281000
1987-01-01	100.20922210
1988-01-01	99.31948273
1989-01-01	99.57236600
1990-01-01	97.84501674
1991-01-01	97.44421147
1992-01-01	98.14631735
1993-01-01	89.83003450
1994-01-01	98.64451785
1995-01-01	99.62515397
1996-01-01	100.79651830
1997-01-01	99.10491500
1998-01-01	116.53211430
1999-01-01	82.31782933
2000-01-01	99.93648949
2001-01-01	89.52867592
2002-01-01	95.67310816
2003-01-01	96.18425553
2004-01-01	95.73381107
2005-01-01	97.67810204
2006-01-01	98.03528310
2007-01-01	100.27923340
2008-01-01	100.58590950
2009-01-01	100.13618370
2010-01-01	97.65315605