Year	Percent
1990	5.64
1991	5.756
1992	6.592
1993	6.632
1994	5.887
1995	6.2892
1996	4.7721
1997	4.3924
1998	3.4857
1999	3.2577
2000	3.6173
2001	3.8489
2002	3.957
2003	4.4566
2004	4.5561
2005	4.549
2006	3.4476
2007	2.5567
2008	2.7171
2009	3.5526
2010	4.0378
2011	3.4165
2012	3.5585
2013	3.5948
2014	3.7063
2015	4.5601
2016	5.3595
2017	4.5821