Year	Percent
1980-01-01	1.560
1981-01-01	1.710
1982-01-01	1.890
1983-01-01	1.770
1984-01-01	1.730
1985-01-01	2.590
1986-01-01	2.510
1987-01-01	3.830
1988-01-01	4.235
1989-01-01	7.095
1990-01-01	7.055
1991-01-01	6.600
1992-01-01	8.100
1993-01-01	11.060
1994-01-01	11.430
1995-01-01	8.840
1996-01-01	11.550
1997-01-01	13.530
1998-01-01	16.880
1999-01-01	15.740
2000-01-01	18.730
2001-01-01	25.940
2002-01-01	31.140
2003-01-01	36.270
2004-01-01	34.180
2005-01-01	36.950
2006-01-01	49.300
2007-01-01	52.880
2008-01-01	50.390
2009-01-01	59.040
2010-01-01	60.410
2011-01-01	55.505
2012-01-01	58.895
2013-01-01	57.610
2014-01-01	46.950
2015-01-01	48.770