Year	Percent
1962-01-01	0.470957059476256
1963-01-01	0.594506155350444
1964-01-01	0.523734126259584
1965-01-01	0.479632345415918
1966-01-01	0.527254830839284
1967-01-01	1.536626253997050
1968-01-01	1.088382479497890
1969-01-01	0.570750903731714
1970-01-01	0.420182549425010
1971-01-01	0.453342048956527
1972-01-01	0.638687497149599
1973-01-01	0.678196782730138
1974-01-01	1.480462358016050
1975-01-01	2.871281366988140
1976-01-01	2.645682007581270
1977-01-01	2.424629488772290
1978-01-01	2.278810424270500
1979-01-01	1.928282143736360
1980-01-01	1.959415058762410
1981-01-01	2.988631906932830
1982-01-01	4.663365051611000
1983-01-01	5.812219910734150
1984-01-01	5.837461068214050
1985-01-01	5.861411410203920
1986-01-01	5.452955694638380
1987-01-01	5.467031612055060
1988-01-01	5.204782608204930
1991-01-01	4.598607970486530
1992-01-01	5.460545460294290
1993-01-01	6.738935755179560
1994-01-01	7.318744106549620
1995-01-01	7.281661550090850
1996-01-01	8.443023418466610
1997-01-01	9.379875976187490
1998-01-01	8.863480202790250
1999-01-01	8.060893379893240
2000-01-01	7.503546047650160
2001-01-01	7.755202876750980
2002-01-01	8.833956063447120
2003-01-01	9.989256794152500
2004-01-01	10.201889301322000
2005-01-01	11.396265018585000
2006-01-01	10.317245989024500
2007-01-01	8.548456816062620
2008-01-01	7.424746207372250
2009-01-01	8.104536773116160
2010-01-01	7.367621266177610
2011-01-01	6.037162344383800
2012-01-01	5.554370176280800
2013-01-01	5.505187604350530
2014-01-01	5.285421133127050
2015-01-01	4.975601675570480
2016-01-01	4.452025043093870
2017-01-01	4.118647580174440