Year	Percent
1991	29.738
1992	27.978
1993	25.443
1994	24.297
1995	23.637
1996	22.724
1997	20.992
1998	18.461
1999	18.86
2000	19.098
2001	18.508
2002	18.156
2003	17.896
2004	17.766
2005	16.585
2006	15.975
2007	15.574
2008	15.185
2009	13.742
2010	14.325
2011	14.365
2012	13.938
2013	13.524
2014	13.636
2015	13.687
2016	13.284
2017	13.141
2018	12.915
2019	12.685
2020	12.463
2021	12.237
2022	12.013