Year	Percent
1991	27.591
1992	27.989
1993	28.118
1994	27.809
1995	27.339
1996	27.373
1997	26.615
1998	28.066
1999	29.561
2000	23.764
2001	21.041
2002	21.931
2003	19.646
2004	16.334
2005	17.49
2006	21.084
2007	19.952
2008	21.685
2009	20.068
2010	17.475
2011	17.18
2012	20.211
2013	21.347
2014	23.861
2015	25.678
2016	28.209
2017	28.372
2018	27.955
2019	27.429
2020	26.958
2021	26.427
2022	25.775