Year	Percent
1991	31.524
1992	27.134
1993	24.709
1994	32.548
1995	31.92
1996	31.44
1997	33.278
1998	30.963
1999	27.911
2000	32.688
2001	31.906
2002	31.449
2003	30.42
2004	32.413
2005	30.379
2006	30.185
2007	29.603
2008	35.175
2009	34.221
2010	35.076
2011	32.796
2012	33.534
2013	35.475
2014	35.18
2015	34.3
2016	35.178
2017	35.244
2018	35.397
2019	35.397
2020	35.55
2021	35.551
2022	35.551