Year	Percent
1991	33.024
1992	36.916
1993	34.457
1994	17.861
1995	32.849
1996	28.776
1997	31.308
1998	27.426
1999	25.683
2000	28.971
2001	29.125
2002	28.362
2003	26.273
2004	25.207
2005	24.75
2006	22.672
2007	19.19
2008	19.968
2009	16.318
2010	21.868
2011	22.019
2012	19.236
2013	22.95
2014	22.018
2015	20.317
2016	21.576
2017	21.574
2018	21.501
2019	21.503
2020	21.485
2021	21.486
2022	21.468