Year	Percent
1990-01-01	52.9859
1991-01-01	55.0692
1992-01-01	52.8585
1993-01-01	49.2079
1994-01-01	51.7831
1995-01-01	55.0168
1996-01-01	52.6786
1997-01-01	48.3526
1998-01-01	46.2534
1999-01-01	43.0320
2000-01-01	40.2281
2001-01-01	38.7113
2002-01-01	37.2164
2003-01-01	37.3473
2004-01-01	33.6019
2005-01-01	27.5782
2006-01-01	23.5412
2007-01-01	26.9500
2008-01-01	34.7829
2009-01-01	50.1939
2010-01-01	57.3506
2011-01-01	54.1547