Year	Percent
1991	13.518
1992	13.513
1993	13.705
1994	13.854
1995	13.953
1996	14.1
1997	14.313
1998	14.618
1999	14.987
2000	14.583
2001	14.373
2002	14.027
2003	14.358
2004	14.734
2005	15.148
2006	15.55
2007	15.268
2008	15.049
2009	14.346
2010	15.035
2011	15.834
2012	16.067
2013	16.079
2014	16.23
2015	17.314
2016	17.423
2017	17.566
2018	17.656
2019	17.719
2020	17.752
2021	17.691
2022	17.587