Year	Percent
1991	11.38
1992	12.337
1993	12.82
1994	13.343
1995	13.693
1996	13.649
1997	13.789
1998	13.11
1999	12.805
2000	12.612
2001	12.958
2002	13.38
2003	13.652
2004	14.089
2005	14.585
2006	15.1
2007	15.759
2008	15.776
2009	16.125
2010	18.062
2011	18.238
2012	18.521
2013	19.348
2014	19.979
2015	19.839
2016	19.904
2017	19.889
2018	19.78
2019	19.693
2020	19.639
2021	19.591
2022	19.537