Year	Percent
1991	8.1837
1992	8.08147
1993	7.79481
1994	6.94525
1995	6.6381
1996	6.21585
1997	5.79335
1998	5.55432
1999	5.31344
2000	5.2193
2001	4.87164
2002	4.89616
2003	4.5128
2004	4.44676
2005	3.97789
2006	3.76443
2007	3.58148
2008	3.17433
2009	3.11691
2010	3.09616
2011	2.98915
2012	3.05025
2013	3.03041
2014	2.74857
2015	2.92548
2016	2.90145
2017	2.8029
2018	2.80224
2019	2.665