Year	Percent
1973-01-01	8.26666666600004
1974-01-01	15.52828175026680
1975-01-01	9.66969548151244
1976-01-01	10.31741588774130
1977-01-01	11.98928332210510
1978-01-01	9.71603274954341
1980-01-01	9.62605664613179
1981-01-01	10.75850341601450
1982-01-01	8.33125575581155
1983-01-01	5.49366551432092
1984-01-01	8.11639795517100
1985-01-01	7.25436179981638
1986-01-01	6.79885844748841
1987-01-01	4.22241666240750
1988-01-01	5.91154496373490
1989-01-01	7.74088603961336
1990-01-01	8.45146240803884
1991-01-01	9.00000000000004
1992-01-01	9.35975158953137
1993-01-01	9.37034415971456
1994-01-01	5.11259890444316
1995-01-01	6.54379068524170
1996-01-01	4.68130623916412
1997-01-01	3.60116103260949
1998-01-01	3.41731948975797
1999-01-01	2.66937369053700
2000-01-01	1.85379035325277
2001-01-01	1.77220437351017
2002-01-01	1.83299389002050
2003-01-01	2.71259247474351
2004-01-01	3.63228004956623
2005-01-01	3.49368534619531
2006-01-01	3.84234125624782
2007-01-01	4.74356585295154
2008-01-01	11.27066523808480
2009-01-01	2.92089711805365
2010-01-01	3.95007875923886
2011-01-01	4.75316388885632
2012-01-01	4.90242727217991
2013-01-01	3.23423783752364
2014-01-01	2.78798830676221
2015-01-01	1.83951987503599
2016-01-01	2.18686161532911
2017-01-01	1.96887556815799