Year	Percent
1990-01-01	49.421600000000000
1991-01-01	57.980900000000000
1992-01-01	56.723900000000000
1993-01-01	51.799100000000000
1994-01-01	48.908500000000000
1995-01-01	45.637400000000000
1996-01-01	41.799800000000000
1997-01-01	39.080100000000000
1998-01-01	37.064800000000000
1999-01-01	35.057400000000000
2000-01-01	34.194900000000000
2001-01-01	35.237500000000000
2002-01-01	37.855400000000000
2003-01-01	40.581100000000000
2004-01-01	41.193000000000005
2005-01-01	38.314900000000000
2006-01-01	39.144900000000000
2007-01-01	46.592900000000000
2008-01-01	51.152900000000000
2009-01-01	53.775300000000000
2010-01-01	55.884400000000000
2011-01-01	56.257600000000000