Year	Percent
1991	38.029
1992	38.211
1993	38.531
1994	38.023
1995	37.882
1996	30.883
1997	33.694
1998	37.504
1999	39.518
2000	38.35
2001	30.151
2002	23.758
2003	26.049
2004	25.924
2005	28.008
2006	28.431
2007	29.428
2008	27.822
2009	27.085
2010	26.683
2011	31.422
2012	32.018
2013	30.916
2014	30.618
2015	33.72
2016	33.672
2017	33.308
2018	33.942
2019	34.394
2020	34.774
2021	35.094
2022	35.35