Year	Percent
1990-01-01	34.5608
1991-01-01	37.6438
1992-01-01	37.8498
1993-01-01	39.9553
1994-01-01	42.1488
1995-01-01	33.6743
1996-01-01	26.5044
1997-01-01	23.6731
1998-01-01	24.2554
1999-01-01	24.9622
2000-01-01	21.6250
2001-01-01	19.8110
2002-01-01	21.2229
2003-01-01	23.9725
2004-01-01	24.7746
2005-01-01	24.4547
2006-01-01	23.7624
2007-01-01	24.6452
2008-01-01	24.9112
2009-01-01	26.2773
2010-01-01	24.5589
2011-01-01	21.4296