Year	Percent
1991	10.542
1992	11.43
1993	11.548
1994	11.668
1995	8.622
1996	9.802
1997	11.081
1998	11.622
1999	9.415
2000	7.286
2001	9.054
2002	11.67
2003	12.39
2004	13.643
2005	14.865
2006	16.818
2007	16.836
2008	17.145
2009	18.384
2010	18.96
2011	18.881
2012	18.708
2013	18.516
2014	19.25
2015	18.73
2016	19.55
2017	19.666
2018	19.809
2019	19.968
2020	20.104
2021	20.238
2022	20.36