Year	Percent
1991	25.177
1992	21.448
1993	23.867
1994	23.777
1995	24.325
1996	22.34
1997	25.716
1998	24.26
1999	25.353
2000	23.404
2001	28.705
2002	29.273
2003	28.94
2004	29.383
2005	26.879
2006	26.282
2007	23.89
2008	24.614
2009	25.224
2010	20.404
2011	15.979
2012	17.208
2013	18.469
2014	18.105
2015	17.893
2016	16.349
2017	16.346
2018	16.321
2019	16.296
2020	16.273
2021	16.251
2022	16.229