Year	Percent
1960-01-01	30.717700000000000
1961-01-01	27.975400000000000
1962-01-01	24.030400000000000
1963-01-01	24.634100000000000
1964-01-01	23.095200000000000
1965-01-01	24.109200000000000
1966-01-01	26.737300000000000
1967-01-01	27.476200000000000
1968-01-01	29.344700000000000
1969-01-01	29.842100000000000
1970-01-01	36.508100000000000
1971-01-01	34.425900000000000
1972-01-01	32.310700000000000
1973-01-01	35.702400000000000
1974-01-01	33.247700000000000
1975-01-01	32.350900000000000
1976-01-01	32.903600000000000
1977-01-01	37.534000000000000
1978-01-01	40.988300000000000
1979-01-01	41.503600000000000
1980-01-01	41.038999999999994
1981-01-01	38.488200000000000
1982-01-01	43.474000000000000
1983-01-01	50.450200000000000
1984-01-01	60.931700000000000
1985-01-01	66.556700000000000
1986-01-01	65.784800000000000
1987-01-01	63.917900000000000
1988-01-01	46.931999999999995
1989-01-01	50.489000000000000
1990-01-01	50.705200000000000
1991-01-01	50.372300000000000
1992-01-01	49.803500000000000
1993-01-01	56.570300000000000
1994-01-01	50.324700000000000
1995-01-01	51.754400000000000
1996-01-01	48.571500000000000
1997-01-01	48.655300000000000
1998-01-01	50.133900000000000
1999-01-01	53.970500000000000
2000-01-01	54.230600000000000
2001-01-01	62.006400000000000
2002-01-01	65.248500000000000
2003-01-01	78.566800000000000
2004-01-01	70.777300000000000
2005-01-01	66.012000000000000
2006-01-01	65.634900000000000
2007-01-01	60.723600000000000
2008-01-01	62.680900000000000
2009-01-01	67.362800000000000
2010-01-01	67.666600000000000