Year	Percent
1991	18.257
1992	17.836
1993	17.743
1994	17.447
1995	17.4
1996	16.077
1997	16.709
1998	17.31
1999	17.553
2000	17.736
2001	18.84
2002	18.679
2003	18.344
2004	19.286
2005	20.687
2006	20.696
2007	17.356
2008	18.186
2009	16.191
2010	15.3
2011	17.73
2012	19.524
2013	20.135
2014	22.875
2015	25.049
2016	25.176
2017	25.133
2018	25.1
2019	25.027
2020	24.973
2021	24.937
2022	24.909