Year	Percent
1980	3.83333
1981	4.28049
1982	4.92405
1983	6.232
1984	7.07317
1985	5.76577
1986	5.65574
1987	6.18321
1988	5.30903
1989	5.94349
1990	5.8613
1991	2.61203
1992	2.96845
1993	2.87088
1994	3.3035
1995	1.46048
1996	1.11168
1997	1.10274
1998	1.13921
1999	1.24587
2000	1.28446
2001	1.24217
2002	1.27364
2003	1.28094
2004	1.36242
2005	0.94623
2006	0.80947
2007	0.73265
2008	0.72824
2009	0.77259
2010	0.97683
2011	0.90526
2012	0.91122
2013	0.98566
2014	1.02441
2015	0.99292
2016	1.0306
2017	0.81466