Year	Percent
1991	6.0281
1992	5.7312
1993	5.45679
1994	5.187
1995	4.89016
1996	4.82319
1997	4.63718
1998	4.41118
1999	4.24333
2000	4.14278
2001	4.07012
2002	4.13116
2003	4.25367
2004	3.87371
2005	3.63652
2006	3.73325
2007	3.45418
2008	2.73792
2009	2.93079
2010	2.90757
2011	2.90942
2012	2.91885
2013	3.07467
2014	2.8453
2015	2.71361
2016	2.86113
2017	2.60477
2018	2.49867
2019	2.5324