Year	Percent
1980-01-01	3.450
1981-01-01	4.815
1982-01-01	2.450
1983-01-01	3.140
1984-01-01	4.490
1985-01-01	7.530
1986-01-01	9.170
1987-01-01	9.050
1988-01-01	9.705
1989-01-01	11.100
1990-01-01	12.025
1991-01-01	13.800
1992-01-01	14.900
1993-01-01	13.760
1994-01-01	15.370
1995-01-01	14.040
1996-01-01	14.500
1997-01-01	15.140
1998-01-01	18.700
1999-01-01	17.935
2000-01-01	23.065
2001-01-01	27.420
2002-01-01	31.080
2003-01-01	35.840
2004-01-01	37.180
2005-01-01	37.085
2006-01-01	46.885
2007-01-01	51.880
2008-01-01	50.065
2009-01-01	62.965
2010-01-01	61.925
2011-01-01	63.750
2012-01-01	62.445
2013-01-01	60.020
2014-01-01	53.820
2015-01-01	60.200