Year	Percent
1991	64.245
1992	64.06
1993	62.66
1994	62.018
1995	61.635
1996	59.816
1997	60.576
1998	60.598
1999	60.647
2000	60.687
2001	57.242
2002	53.561
2003	49.582
2004	45.866
2005	41.988
2006	41.942
2007	42.147
2008	42.008
2009	41.628
2010	40.93
2011	42.837
2012	42.885
2013	42.042
2014	38.902
2015	34.7
2016	32.909
2017	30.615
2018	29.053
2019	27.714
2020	26.5
2021	25.324
2022	24.463