Year	Percent
1987-01-01	2.7633400000000004
1988-01-01	1.9282400000000002
1989-01-01	1.9321700000000002
1990-01-01	2.0146700000000000
1991-01-01	2.0136700000000003
1992-01-01	2.5184700000000000
1993-01-01	4.0329300000000000
1994-01-01	5.0595000000000000
1995-01-01	5.1765500000000000
1996-01-01	5.2417200000000000
1997-01-01	6.5538500000000000
1998-01-01	13.5247000000000000
1999-01-01	13.1367000000000000
2000-01-01	13.1975000000000000
2001-01-01	14.1440000000000000
2002-01-01	14.6742000000000000
2003-01-01	15.4625000000000000
2004-01-01	15.1794000000000000
2005-01-01	14.1628000000000000
2006-01-01	13.2537000000000000
2007-01-01	15.0919000000000000
2008-01-01	17.2279999999999980
2009-01-01	19.5554000000000000
2010-01-01	23.9200000000000000