Year	Percent
1991	17.448
1992	17.514
1993	18.927
1994	19.679
1995	19.77
1996	18.256
1997	17.511
1998	16.888
1999	16.412
2000	16.155
2001	7.309
2002	10.302
2003	7.588
2004	7.393
2005	6.004
2006	7.733
2007	6.401
2008	4.186
2009	3.626
2010	3.78
2011	3.454
2012	3.598
2013	3.494
2014	3.204
2015	4.244
2016	3.896
2017	3.849
2018	3.781
2019	3.68
2020	3.724
2021	3.701
2022	3.647