Year	Percent
1990	2.2934
1991	2.34874
1992	2.66268
1993	2.84268
1994	3.16949
1995	3.16711
1996	3.26013
1997	3.27518
1998	3.20334
1999	2.84791
2000	2.65503
2001	2.20135
2002	1.93239
2003	1.97321
2004	2.27626
2005	2.22477
2006	2.1622
2007	1.85591
2008	1.58926
2009	1.95476
2010	2.09185
2011	2.17517
2012	2.19473
2013	2.33487
2014	2.57595
2015	2.58164
2016	2.5408
2017	2.38927