Year	Percent
1970-01-01	6.599999999000150
1971-01-01	2.626641651056340
1972-01-01	3.656307129832340
1973-01-01	6.172839506227160
1974-01-01	4.699612403416970
1975-01-01	8.230316652651410
1976-01-01	9.430735401745540
1977-01-01	11.989283322105100
1978-01-01	17.523923445503300
1979-01-01	11.348600508609100
1980-01-01	9.517824497549650
1981-01-01	14.654842636063400
1982-01-01	6.542509630076670
1983-01-01	5.967163930327240
1984-01-01	8.116397955171000
1985-01-01	10.482287044446800
1986-01-01	12.371609165129800
1987-01-01	7.441260912872520
1988-01-01	5.911544963734900
1989-01-01	9.304361258431650
1990-01-01	16.652534388543300
1991-01-01	25.886386934851300
1992-01-01	31.669661911714900
1993-01-01	20.540326123582600
1994-01-01	29.047656117307100
1995-01-01	29.779626486500000
1996-01-01	18.679075860174900
1997-01-01	5.733522753571860
1998-01-01	4.950161637931150
1999-01-01	2.645511133927980
2000-01-01	0.339163189071752
2001-01-01	4.225988348546800
2002-01-01	1.418301923450430
2003-01-01	4.268953958395020
2004-01-01	3.961800302571890
2005-01-01	1.382446566621190
2006-01-01	2.314524087198360
2007-01-01	3.673827268741700
2008-01-01	4.862990527740240
2009-01-01	5.734333413985010
2010-01-01	3.913043478260830
2011-01-01	4.524211505052760
2012-01-01	8.891450910623140
2013-01-01	3.254239109988470
2014-01-01	2.916926920674570
2015-01-01	4.784447006938940
2016-01-01	6.397694802687490
2017-01-01	5.591115909616730