Year	Percent
1991	12.175
1992	12.051
1993	11.748
1994	11.722
1995	11.465
1996	11.184
1997	11.005
1998	11.183
1999	11.389
2000	11.453
2001	11.609
2002	11.939
2003	12.053
2004	12.198
2005	12.32
2006	12.235
2007	12.159
2008	12.056
2009	12.004
2010	11.911
2011	11.752
2012	11.826
2013	11.865
2014	12.006
2015	11.932
2016	11.491
2017	11.711
2018	11.864
2019	12.011
2020	12.152
2021	12.292
2022	12.43