Year	Percent
1991	25.376
1992	27.887
1993	27.025
1994	21.889
1995	23.584
1996	25.514
1997	21.959
1998	20.532
1999	19.261
2000	18.698
2001	18.867
2002	18.449
2003	19.239
2004	20.411
2005	22.013
2006	22.699
2007	22.514
2008	24.851
2009	25.271
2010	25.173
2011	24.847
2012	24.661
2013	24.676
2014	24.602
2015	24.412
2016	23.742
2017	23.903
2018	23.643
2019	23.427
2020	23.175
2021	22.989
2022	22.788