Year	Percent
1991	57.122
1992	54.6
1993	53.24
1994	52.306
1995	51.107
1996	46.636
1997	41.227
1998	39.177
1999	34.558
2000	34.208
2001	32.563
2002	30.645
2003	37.776
2004	34.301
2005	34.752
2006	37.528
2007	39.415
2008	40.504
2009	31.225
2010	27.165
2011	33.289
2012	34.582
2013	33.928
2014	33.743
2015	39.944
2016	39.272
2017	38.631
2018	37.205
2019	35.759
2020	34.465
2021	33.379
2022	32.494