Year	Percent
1991	11.22425
1992	11.41858
1993	11.78798
1994	11.70142
1995	11.37626
1996	10.93254
1997	10.6268
1998	10.35281
1999	10.44065
2000	10.10924
2001	9.83262
2002	9.61018
2003	9.34299
2004	9.00227
2005	8.63043
2006	8.68562
2007	8.65429
2008	7.60887
2009	6.97158
2010	6.18092
2011	5.46998
2012	5.27584
2013	4.55591
2014	5.67583
2015	7.7198
2016	7.74347
2017	7.93542
2018	8.01903
2019	7.14643