Year	Percent
1971-01-01	1.7314900000000002
1972-01-01	1.3522299999999998
1973-01-01	0.9949600000000001
1974-01-01	0.8112860000000000
1975-01-01	0.6374750000000000
1976-01-01	0.4127640000000000
1977-01-01	0.3162330000000000
1978-01-01	0.9206530000000000
1979-01-01	0.9116930000000000
1980-01-01	0.3338260000000000
1981-01-01	1.0515700000000001
1982-01-01	2.6480099999999998
1983-01-01	4.5871500000000000
1984-01-01	6.0174699999999990
1985-01-01	7.0649200000000000
1986-01-01	8.0542400000000000
1987-01-01	8.5863900000000000
1988-01-01	9.9972900000000000
1989-01-01	7.8335200000000000
1990-01-01	5.3144900000000000
1991-01-01	5.2610300000000000
1992-01-01	8.0504600000000010
1993-01-01	11.2130000000000000
1994-01-01	17.0258000000000000
1995-01-01	24.6948000000000000
1996-01-01	28.9753000000000000
1997-01-01	30.2560000000000000
1998-01-01	23.5728000000000000
1999-01-01	18.1312000000000000
2000-01-01	18.7415000000000000
2001-01-01	20.6612000000000000
2002-01-01	27.3615000000000000
2003-01-01	30.5006000000000000
2004-01-01	26.2904000000000000
2005-01-01	27.5489000000000000
2006-01-01	22.0679000000000000
2007-01-01	15.9021000000000000
2008-01-01	12.4329000000000000
2009-01-01	9.3718600000000000
2010-01-01	9.3143700000000000
2011-01-01	9.3596700000000000
2012-01-01	8.2405900000000000
2013-01-01	7.4505800000000000
2014-01-01	6.9295300000000010
2015-01-01	6.6107900000000000
2016-01-01	6.2130800000000010