Year	Percent
1970-01-01	4.05924693025549
1971-01-01	3.87562123955683
1972-01-01	3.70773884352750
1973-01-01	7.07186753470659
1974-01-01	12.13662664495260
1975-01-01	9.59343641278391
1976-01-01	10.78677919697620
1977-01-01	12.29314215705600
1978-01-01	10.39706656607870
1979-01-01	9.90436051231126
1980-01-01	11.58456734164850
1981-01-01	11.84612549979480
1982-01-01	10.39330807646340
1983-01-01	6.16761386479386
1984-01-01	9.22951819475498
1985-01-01	7.72863890085919
1986-01-01	12.37160916512980
1987-01-01	7.44126091287252
1988-01-01	6.90509807493765
1989-01-01	10.35178923978330
1990-01-01	12.32179998478110
1991-01-01	14.51233162226310
1992-01-01	12.32329924182420
1993-01-01	12.65646639138280
1994-01-01	11.74134921957780
1995-01-01	11.86109415403320
1996-01-01	6.84416086199789
1997-01-01	3.65202620723074
1998-01-01	3.87257546427492
1999-01-01	2.69012485811580
2000-01-01	2.68380535348548
2001-01-01	2.12654526904646
2002-01-01	2.72913569925395
2003-01-01	4.33599308785194
2004-01-01	3.79704017606906
2005-01-01	3.80046802667732
2006-01-01	5.37111909102892
2007-01-01	4.32563767869380
2008-01-01	12.31073675828900
2009-01-01	2.92089711805365
2010-01-01	3.98347941855833
2011-01-01	4.97148571692381
2012-01-01	6.08909641595155
2013-01-01	4.03762933648119
2014-01-01	2.89893170350572
2015-01-01	1.49475928578370
2016-01-01	2.18686161532911
2017-01-01	3.82290472736717