Year	Percent
1980-01-01	2.2250300000000000
1981-01-01	1.9492900000000002
1982-01-01	2.2611400000000000
1983-01-01	2.0309200000000000
1984-01-01	1.8239000000000000
1985-01-01	2.2147200000000002
1986-01-01	2.9913100000000000
1987-01-01	3.4955000000000000
1988-01-01	3.1824200000000000
1989-01-01	1.7924600000000000
1990-01-01	1.8918900000000000
1991-01-01	1.7710200000000000
1992-01-01	1.3866700000000000
1993-01-01	1.5812000000000000
1994-01-01	1.8786100000000000
1995-01-01	1.4108700000000000
1996-01-01	3.3563300000000003
1997-01-01	5.0029800000000000
1998-01-01	8.8845400000000000
1999-01-01	11.9268000000000000
2000-01-01	15.0463000000000000
2001-01-01	23.5241000000000000
2002-01-01	21.8219000000000000
2003-01-01	27.7912000000000000
2004-01-01	30.5634000000000000
2005-01-01	29.7121000000000000
2006-01-01	28.8369000000000000
2007-01-01	25.7684000000000000
2008-01-01	25.4715000000000000
2009-01-01	25.7509999999999980
2010-01-01	22.5998000000000000
2011-01-01	22.5156000000000000
2012-01-01	26.5247000000000000
2013-01-01	30.9814000000000000
2014-01-01	30.7509000000000000
2015-01-01	29.3895000000000000