Year	Percent
1991	10.17435
1992	10.45291
1993	9.76195
1994	9.06138
1995	9.57317
1996	9.97676
1997	9.08437
1998	8.64771
1999	8.91631
2000	8.71252
2001	7.71218
2002	7.36886
2003	6.98457
2004	6.32086
2005	6.52999
2006	6.31367
2007	5.91938
2008	4.60393
2009	4.83429
2010	5.58671
2011	5.48862
2012	5.54867
2013	4.44485
2014	4.53534
2015	4.23862
2016	3.89526
2017	3.75654
2018	4.03008
2019	4.03555