Year	Percent
1991	10.972
1992	10.303
1993	11.185
1994	11.469
1995	12.387
1996	12.156
1997	11.974
1998	12.732
1999	11.983
2000	13.722
2001	12.565
2002	12.653
2003	13.087
2004	12.76
2005	12.081
2006	11.638
2007	11.726
2008	11.401
2009	11.809
2010	11.697
2011	11.874
2012	11.971
2013	11.976
2014	12.176
2015	12.309
2016	12.496
2017	12.511
2018	12.574
2019	12.657
2020	12.736
2021	12.825
2022	12.936