Year	Percent
1990-01-01	34.351100000000000
1991-01-01	37.771600000000000
1992-01-01	35.313400000000000
1993-01-01	34.059700000000000
1994-01-01	37.833100000000000
1995-01-01	38.820800000000000
1996-01-01	36.873800000000000
1997-01-01	32.870500000000000
1998-01-01	30.661100000000000
1999-01-01	29.211700000000000
2000-01-01	27.375300000000000
2001-01-01	27.205100000000000
2002-01-01	29.734100000000000
2003-01-01	33.079500000000000
2004-01-01	34.074700000000000
2005-01-01	34.096700000000000
2006-01-01	33.927100000000000
2007-01-01	35.278100000000000
2008-01-01	35.388000000000005
2009-01-01	38.587900000000000
2010-01-01	45.817000000000000
2011-01-01	48.770200000000000