Year	Percent
1991	35.603
1992	32.571
1993	26.279
1994	30.971
1995	29.674
1996	30.259
1997	27.29
1998	27.567
1999	28.441
2000	24.573
2001	24.146
2002	23.825
2003	21.531
2004	19.709
2005	19.382
2006	19.305
2007	19.375
2008	19.827
2009	19.455
2010	20.4
2011	21.402
2012	20.946
2013	21.739
2014	22.173
2015	23.175
2016	23.366
2017	22.683
2018	22.98
2019	22.881
2020	23.083
2021	23.26
2022	23.404