Year	Percent
1991	15.633
1992	15.111
1993	15.655
1994	15.709
1995	16.209
1996	16.025
1997	17.827
1998	16.234
1999	12.699
2000	16.631
2001	20.428
2002	24.674
2003	28.032
2004	32.071
2005	35.136
2006	36.521
2007	37.336
2008	33.177
2009	33.906
2010	33.375
2011	32.886
2012	32.402
2013	31.95
2014	32.433
2015	32.612
2016	32.755
2017	33.042
2018	33.038
2019	33.245
2020	33.494
2021	33.814
2022	34.129