Year	Percent
1991	22.406
1992	23.494
1993	19.855
1994	17.599
1995	14.439
1996	13.556
1997	14.922
1998	15.442
1999	15.264
2000	17.282
2001	16.827
2002	15.448
2003	18.855
2004	22.527
2005	22.9
2006	25.667
2007	26.958
2008	27.567
2009	29.609
2010	29.341
2011	29.11
2012	28.838
2013	26.238
2014	26.441
2015	27.699
2016	29.092
2017	29.136
2018	29.422
2019	29.225
2020	29.311
2021	29.501
2022	29.482