Year	Percent
1991	47.318
1992	46.484
1993	43.493
1994	41.28
1995	33.087
1996	34.406
1997	38.565
1998	40.47
1999	38.348
2000	37.281
2001	32.518
2002	28.211
2003	36.324
2004	40.249
2005	40.906
2006	42.672
2007	43.272
2008	42.191
2009	41.552
2010	42.404
2011	41.337
2012	41.597
2013	40.217
2014	39.046
2015	38.167
2016	35.918
2017	35.772
2018	35.801
2019	35.687
2020	35.041
2021	34.513
2022	34.094