Year	Percent
1991	37.205
1992	35.981
1993	30.217
1994	31.757
1995	35.494
1996	35.775
1997	39.149
1998	35.946
1999	32.782
2000	33.727
2001	33.036
2002	34.428
2003	33.278
2004	32.227
2005	31.18
2006	30.252
2007	30.356
2008	28.938
2009	28.962
2010	26.411
2011	29.278
2012	32.452
2013	25.107
2014	21.343
2015	23.703
2016	25.814
2017	26.863
2018	25.707
2019	25.669
2020	25.644
2021	25.492
2022	25.244