Year	Percent
1991	12.652
1992	12.902
1993	13.525
1994	13.589
1995	13.525
1996	13.532
1997	13.435
1998	11.431
1999	9.767
2000	12.381
2001	16.711
2002	20.905
2003	22.512
2004	25.576
2005	25.95
2006	30.426
2007	31.248
2008	34.187
2009	30.935
2010	28.487
2011	27.506
2012	27.69
2013	27.425
2014	26.913
2015	25.943
2016	26.881
2017	26.649
2018	26.15
2019	25.576
2020	24.832
2021	24.582
2022	24.302