Year	Percent
1990-01-01	25.780
1991-01-01	27.600
1992-01-01	26.490
1993-01-01	26.560
1994-01-01	29.305
1995-01-01	30.455
1996-01-01	28.990
1997-01-01	26.685
1998-01-01	26.745
1999-01-01	29.300
2000-01-01	27.580
2001-01-01	24.580
2002-01-01	26.925
2003-01-01	31.585
2004-01-01	32.570
2005-01-01	27.580
2006-01-01	26.930
2007-01-01	29.080
2008-01-01	34.780
2009-01-01	37.660
2010-01-01	39.120
2011-01-01	37.790