Year	Percent
1990	3.32984
1991	2.2841
1992	6.1377
1993	6.26302
1994	6.14274
1995	9.56328
1996	9.3247
1997	8.91953
1998	8.46877
1999	8.12217
2000	7.85296
2001	7.58223
2002	7.16833
2003	7.03782
2004	6.23735
2005	7.29108
2007	6.51777
2008	6.93966
2009	6.79017
2010	6.67065
2011	6.53314
2012	6.3973
2013	6.26185
2014	6.12818
2015	5.99912
2016	5.93182
2017	5.76057
2018	5.83747
2019	5.5297
2020	5.63573