Year	Percent
1991	28.716
1992	28.242
1993	32.618
1994	32.554
1995	33.14
1996	31.838
1997	31.193
1998	28.432
1999	30.305
2000	28.568
2001	27.853
2002	29.861
2003	29.328
2004	28.43
2005	29.973
2006	31.046
2007	31.415
2008	32.936
2009	33.933
2010	40.151
2011	44.495
2012	43.844
2013	42.214
2014	41.704
2015	41.829
2016	42.108
2017	43.649
2018	43.447
2019	43.115
2020	42.663
2021	42.115
2022	41.597