Year	Percent
1991	42.548
1992	42.344
1993	38.048
1994	37.453
1995	36.421
1996	36.984
1997	40.333
1998	37.171
1999	35.212
2000	35.181
2001	33.827
2002	33.658
2003	31.247
2004	29.079
2005	27.068
2006	25.244
2007	24.256
2008	22.879
2009	20.595
2010	19.255
2011	19.924
2012	20.646
2013	14.926
2014	13.815
2015	13.316
2016	15.705
2017	16.353
2018	16.019
2019	16.221
2020	16.341
2021	16.322
2022	16.166