Year	Percent
1991	17.016
1992	16.995
1993	16.529
1994	17.093
1995	17.212
1996	18.226
1997	13.381
1998	16.11
1999	15.276
2000	13.929
2001	8.066
2002	9.663
2003	9.072
2004	10.363
2005	8.519
2006	9.35
2007	9.321
2008	9.7
2009	9.753
2010	9.372
2011	9.489
2012	9.826
2013	9.605
2014	9.513
2015	9.469
2016	9.832
2017	10.109
2018	10.121
2019	10.027
2020	9.846
2021	9.589
2022	9.326