Year	Percent
1992-01-01	19.639700000000000
1993-01-01	20.855600000000000
1994-01-01	22.973000000000003
1995-01-01	23.439800000000000
1996-01-01	23.701300000000000
1997-01-01	25.050500000000000
1998-01-01	27.654400000000000
1999-01-01	29.089100000000000
2000-01-01	29.765500000000000
2001-01-01	31.340100000000000
2002-01-01	35.150700000000000
2003-01-01	40.403000000000000
2004-01-01	42.548500000000000
2005-01-01	40.976000000000006
2006-01-01	39.622300000000000
2007-01-01	40.931900000000000
2008-01-01	39.613000000000000
2009-01-01	42.926100000000000
2010-01-01	48.612800000000000
2011-01-01	50.050300000000000