Year	Percent
1991	11.58187
1992	11.25739
1993	9.129
1994	8.7501
1995	8.09064
1996	8.21928
1997	7.81151
1998	7.34184
1999	6.95391
2000	6.46251
2001	6.1869
2002	6.1178
2003	5.3815
2004	5.26059
2005	4.86641
2006	4.7637
2007	4.58641
2008	4.3146
2009	4.60901
2010	4.5406
2011	4.8859
2012	5.0637
2013	4.7773
2014	4.67525
2015	4.90016
2016	5.03976
2017	5.0367
2018	4.84821
2019	4.73273