Year	Percent
1984	2.04
1985	2.02
1986	0.96
1989	0.92
1991	2.2
1996	2.51
2000	3.27
2003	4.32
2005	4.25
2006	3.59
2009	5
2010	3.38
2013	4.43
2016	4.35
2017	4.37