Year	Percent
1980-01-01	29.4408
1981-01-01	35.0490
1982-01-01	32.7112
1983-01-01	33.5703
1984-01-01	29.7364
1985-01-01	23.8034
1986-01-01	22.7050
1987-01-01	21.1715
1988-01-01	28.3412
1989-01-01	27.9814
1990-01-01	24.6148
1991-01-01	26.4929
1992-01-01	27.3545
1993-01-01	44.0118
1994-01-01	29.0296
1995-01-01	30.0136
1996-01-01	26.4544
1997-01-01	27.6504
1998-01-01	26.4434
1999-01-01	29.0548
2000-01-01	27.1073
2001-01-01	28.8928
2002-01-01	25.5227
2003-01-01	30.5875
2004-01-01	23.3105
2005-01-01	20.5719
2006-01-01	19.0535
2007-01-01	21.4566
2008-01-01	24.3657
2009-01-01	24.5446
2010-01-01	24.7050