Year	Percent
1981-01-01	12.44243689361770
1982-01-01	10.22172713768910
1983-01-01	8.66927159808515
1984-01-01	8.08032017255761
1985-01-01	6.80756655768336
1986-01-01	5.73355817902006
1987-01-01	5.66377475855217
1988-01-01	7.14609525631211
1989-01-01	6.76613761472792
1990-01-01	8.08053258202096
1991-01-01	8.96562265214311
1992-01-01	7.54090626670037
1993-01-01	6.78377994665411
1994-01-01	10.29898688021050
1995-01-01	9.15385347503376
1996-01-01	6.55097336065570
1997-01-01	5.53600678399903
1998-01-01	5.11024301619077
1999-01-01	3.23183260906467
2000-01-01	3.49446497607157
2001-01-01	3.99490488060284
2002-01-01	2.90799857032208
2003-01-01	3.03923368432095
2004-01-01	3.41399094600655
2005-01-01	4.09348246957889
2006-01-01	4.28554926648962
2007-01-01	4.80370641306989
2008-01-01	8.95773218758907
2009-01-01	2.91712777327418
2010-01-01	3.36239155274532
2011-01-01	4.83940349870950
2012-01-01	3.72108721983356
2013-01-01	2.59425284430657
2014-01-01	2.35037959246004
2015-01-01	1.44385754500356
2016-01-01	1.47171045649997
2017-01-01	2.17715123516459