Year	Percent
1991	6.457
1992	7.992
1993	6.389
1994	6.101
1995	5.526
1996	6.131
1997	6.325
1998	5.131
1999	5.229
2000	4.122
2001	4.789
2002	4.879
2003	5.424
2004	4.144
2005	4.266
2006	4.47
2007	3.477
2008	3.058
2009	3.778
2010	3.709
2011	4.316
2012	3.405
2013	3.738
2014	4.384
2015	4.244
2016	3.859
2017	3.945
2018	3.918
2019	3.881
2020	3.838
2021	3.791
2022	3.741