Year	Percent
1991	16.718
1992	16.271
1993	16.08
1994	15.737
1995	15.524
1996	15.294
1997	14.686
1998	14.211
1999	13.756
2000	13.374
2001	13.478
2002	15.854
2003	15.106
2004	15.418
2005	13.905
2006	13.928
2007	14.31
2008	13.808
2009	13.884
2010	14.458
2011	13.584
2012	13.579
2013	13.957
2014	13.897
2015	13.985
2016	13.628
2017	13.415
2018	13.338
2019	13.243
2020	13.166
2021	13.096
2022	13.03