Year	Percent
1973-01-01	22.121200000000000
1974-01-01	21.607200000000000
1975-01-01	23.340400000000000
1976-01-01	27.663400000000000
1977-01-01	32.486400000000000
1978-01-01	30.928200000000000
1979-01-01	29.594700000000000
1980-01-01	30.771400000000000
1981-01-01	33.127800000000000
1982-01-01	38.525200000000000
1983-01-01	38.818900000000000
1984-01-01	39.010800000000000
1985-01-01	32.559100000000000
1986-01-01	28.017200000000000
1987-01-01	28.286800000000000
1988-01-01	26.361200000000000
1989-01-01	33.207500000000000
1990-01-01	31.004800000000000
1991-01-01	31.384600000000000
1992-01-01	33.656200000000000
1993-01-01	44.674100000000000
1994-01-01	39.577200000000000
1995-01-01	36.993700000000000
1996-01-01	35.347300000000000
1997-01-01	35.393000000000000
1998-01-01	35.345600000000000
1999-01-01	36.028900000000000
2000-01-01	33.814400000000000
2001-01-01	34.645400000000000
2002-01-01	31.733400000000000
2003-01-01	36.898300000000000
2004-01-01	33.306900000000000
2005-01-01	30.902300000000000
2006-01-01	32.181999999999995
2007-01-01	32.050300000000000
2008-01-01	36.430300000000000
2009-01-01	41.160400000000000
2010-01-01	42.714000000000000