Year	Percent
1991	16.769
1992	15.466
1993	15.471
1994	15.501
1995	15.954
1996	15.686
1997	16.4
1998	16.607
1999	17.932
2000	19.801
2001	18.004
2002	18.583
2003	19.9
2004	19.098
2005	19.008
2006	21.379
2007	23.892
2008	19.321
2009	17.345
2010	18.788
2011	20.018
2012	18.918
2013	19.371
2014	19.507
2015	19.474
2016	19.366
2017	19.363
2018	19.369
2019	19.376
2020	19.382
2021	19.388
2022	19.393