Year	Percent
1966-01-01	97.95920000000000
1967-01-01	97.63960000000000
1968-01-01	97.65970000000000
1969-01-01	97.99160000000000
1970-01-01	97.93400000000000
1971-01-01	97.55200000000000
1972-01-01	97.44420000000000
1973-01-01	96.85380000000000
1974-01-01	94.20150000000000
1975-01-01	92.33270000000000
1976-01-01	91.95500000000000
1977-01-01	87.87700000000001
1978-01-01	87.82010000000000
1979-01-01	89.25940000000000
1980-01-01	88.56500000000000
1981-01-01	88.43370000000000
1982-01-01	88.79600000000000
1983-01-01	90.56560000000000
1984-01-01	91.65370000000000
1985-01-01	92.31220000000000
1986-01-01	92.96930000000000
1987-01-01	94.15010000000000
1988-01-01	94.55900000000000
1989-01-01	93.15360000000000
1990-01-01	91.05570000000000
1991-01-01	89.18500000000000
1992-01-01	88.85480000000000
1993-01-01	90.03530000000000
1994-01-01	90.90010000000000
1995-01-01	93.68230000000000
1996-01-01	96.76450000000000
1997-01-01	97.80710000000000
1998-01-01	98.32260000000000
1999-01-01	98.19130000000000
2000-01-01	98.71900000000000
2001-01-01	99.22640000000000
2002-01-01	98.96280000000000
2003-01-01	99.13760000000000
2004-01-01	98.96060000000000
2005-01-01	97.77620000000000
2006-01-01	97.45590000000000
2007-01-01	98.14620000000000
2008-01-01	97.28920000000000
2009-01-01	96.08650000000000