Year	Percent
1990-01-01	29.0842
1991-01-01	27.8376
1992-01-01	26.0004
1993-01-01	25.3509
1994-01-01	27.9368
1995-01-01	29.7320
1996-01-01	29.5565
1997-01-01	30.3512
1998-01-01	31.3077
1999-01-01	31.0422
2000-01-01	31.7891
2001-01-01	32.9723
2002-01-01	35.1718
2003-01-01	39.4941
2004-01-01	40.4437
2005-01-01	39.7331
2006-01-01	41.6198
2007-01-01	47.4504
2008-01-01	51.7337
2009-01-01	57.3629
2010-01-01	59.4141
2011-01-01	47.9674