Year	Percent
1991	37.736
1992	38.687
1993	37.969
1994	35.468
1995	36.669
1996	36.719
1997	35.512
1998	35.411
1999	36.687
2000	37.035
2001	36.25
2002	34.351
2003	32.3
2004	28
2005	24.874
2006	24.855
2007	22.345
2008	25.986
2009	20.375
2010	18.777
2011	18.438
2012	18.97
2013	19.023
2014	19.175
2015	21.051
2016	24.457
2017	24.574
2018	24.633
2019	24.664
2020	24.647
2021	24.62
2022	24.564