Year	Percent
1993	6.27069
1994	6.07299
1995	5.6427
1996	5.32969
1997	4.47046
1998	4.56916
1999	19.29921
2000	19.10972
2001	15.98423
2002	15.43236
2003	17.2558
2004	16.40168
2005	16.16663
2007	15.72838
2008	15.19732
2009	14.71253
2010	14.36096
2011	14.01152
2012	13.74602
2013	13.47705
2014	13.41413
2015	13.30135
2016	13.22936
2017	13.07233
2018	12.81924
2019	12.55387
2020	12.37631