Year	Percent
1991	14.92
1992	14.389
1993	14.519
1994	14.798
1995	15.329
1996	16.21
1997	16.105
1998	16.648
1999	16.355
2000	15.079
2001	14.913
2002	15.714
2003	15.738
2004	15.957
2005	15.584
2006	16.673
2007	16.795
2008	16.535
2009	17.059
2010	16.163
2011	14.749
2012	15.937
2013	16.592
2014	17.187
2015	16.569
2016	16.469
2017	15.918
2018	15.979
2019	16.083
2020	16.224
2021	16.381
2022	16.55