Year	Percent
1991	14.24454
1992	15.42179
1993	15.56102
1994	16.1502
1995	15.77723
1996	15.27223
1997	12.16208
1998	11.69227
1999	15.00914
2000	14.49333
2001	12.04571
2002	11.33641
2003	10.80132
2004	10.48172
2005	10.14038
2006	9.8758
2007	8.99286
2008	8.53265
2009	8.26831
2010	7.7474
2011	7.68627
2012	7.32613
2013	6.99231
2014	6.72441
2015	6.70982
2016	6.71781
2017	5.9019
2018	5.88259
2019	5.83205