Year	Percent
1991	21.115
1992	20.793
1993	21.897
1994	20.805
1995	20.981
1996	20.349
1997	19.951
1998	19.796
1999	18.851
2000	19.012
2001	19.206
2002	21.29
2003	20.781
2004	21.88
2005	21.979
2006	22.581
2007	22.962
2008	22.871
2009	22.423
2010	22.272
2011	24.17
2012	23.782
2013	22.864
2014	23.671
2015	23.816
2016	23.647
2017	23.658
2018	23.553
2019	23.631
2020	23.694
2021	23.771
2022	23.831