Year	Percent
1960-01-01	31.39980000000000
1961-01-01	33.82140000000000
1962-01-01	36.98240000000000
1963-01-01	39.78910000000000
1964-01-01	34.11980000000000
1965-01-01	32.14420000000000
1966-01-01	33.79260000000000
1967-01-01	37.28740000000000
1968-01-01	38.38610000000000
1969-01-01	40.40050000000000
1970-01-01	40.70220000000000
1971-01-01	46.79570000000000
1972-01-01	51.69150000000000
1973-01-01	57.19870000000000
1974-01-01	63.96630000000000
1975-01-01	85.01850000000000
1976-01-01	85.13930000000000
1977-01-01	93.08440000000000
1978-01-01	98.53890000000000
1979-01-01	105.06500000000000
1980-01-01	109.62600000000000
1981-01-01	120.28000000000000
1982-01-01	121.30799999999999
1983-01-01	121.71300000000000
1984-01-01	122.28800000000000
1985-01-01	139.42800000000000
1986-01-01	154.73200000000000
1987-01-01	183.98600000000000
1988-01-01	221.78599999999997
1989-01-01	239.52700000000002
1990-01-01	249.93599999999998
1991-01-01	238.78900000000002
1992-01-01	255.98900000000000
1993-01-01	255.98900000000000
1994-01-01	255.98900000000000
1995-01-01	276.41600000000000
1996-01-01	279.82800000000000
1997-01-01	301.79800000000000
1998-01-01	301.79800000000000
1999-01-01	301.79800000000000
2000-01-01	292.37600000000000
2001-01-01	312.11700000000000
2002-01-01	298.21100000000000
2003-01-01	286.46900000000000
2004-01-01	299.29000000000000
2005-01-01	328.88599999999997
2006-01-01	361.94900000000000
2007-01-01	380.21200000000000
2008-01-01	399.11400000000003
2009-01-01	381.96700000000000
2010-01-01	339.11699999999996
2011-01-01	330.60200000000000