Year	Percent
1991	8.187
1992	8.215
1993	8.405
1994	8.551
1995	8.715
1996	8.905
1997	9.163
1998	9.456
1999	9.592
2000	10.941
2001	13.839
2002	13.368
2003	12.576
2004	11.678
2005	10.836
2006	10.234
2007	9.563
2008	9.145
2009	9.116
2010	8.95
2011	8.838
2012	9.343
2013	9.706
2014	10.167
2015	10.403
2016	10.457
2017	10.693
2018	10.903
2019	11.318
2020	11.461
2021	11.59
2022	11.717