Year	Percent
1991	4.69
1992	4.784
1993	4.822
1994	5.058
1995	5.016
1996	4.992
1997	5.024
1998	4.853
1999	10.062
2000	9.819
2001	9.855
2002	9.57
2003	9.488
2004	8.879
2005	8.764
2006	8.509
2007	7.962
2008	7.187
2009	7.244
2010	7.142
2011	17.272
2012	16.406
2013	17.101
2014	17.171
2015	16.428
2016	16.311
2017	17.134
2018	17.146
2019	17.111
2020	17.084
2021	16.98
2022	16.776