Year	Percent
1975-01-01	9.984370000000000
1976-01-01	9.813989999999999
1977-01-01	9.627800000000000
1978-01-01	8.573269999999999
1979-01-01	7.544339999999999
1980-01-01	7.361260000000001
1981-01-01	8.562970000000000
1982-01-01	9.021970000000000
1983-01-01	12.766200000000000
1984-01-01	14.440200000000000
1985-01-01	17.986500000000000
1986-01-01	21.207400000000000
1987-01-01	18.735500000000000
1988-01-01	20.620400000000000
1989-01-01	28.911800000000000
1990-01-01	31.306500000000000
1991-01-01	29.681500000000000
1992-01-01	26.272900000000000
1993-01-01	24.510900000000000
1994-01-01	28.126500000000000
1995-01-01	29.690700000000000
1996-01-01	33.473400000000000
1997-01-01	45.039100000000000
1998-01-01	54.160900000000000
1999-01-01	54.215500000000000
2000-01-01	59.812300000000000
2001-01-01	59.130900000000000
2002-01-01	46.904600000000000
2003-01-01	49.246400000000000
2004-01-01	56.977800000000000
2005-01-01	62.529400000000000
2006-01-01	72.799700000000000
2007-01-01	83.021700000000000
2008-01-01	61.684700000000000
2009-01-01	48.967900000000000
2010-01-01	64.410900000000000
2011-01-01	62.430300000000000
2012-01-01	61.184100000000000