Year	Percent
1991	12.695
1992	9.326
1993	10.917
1994	11.416
1995	11.903
1996	12.821
1997	10.636
1998	11.321
1999	11.192
2000	9.828
2001	10.329
2002	9.232
2003	11.249
2004	14.133
2005	11.039
2006	11.464
2007	12.698
2008	10.702
2009	11.597
2010	11.752
2011	12.256
2012	12.548
2013	12.353
2014	12.416
2015	11.992
2016	12.214
2017	12.513
2018	12.488
2019	12.423
2020	12.419
2021	12.42
2022	12.423