Year	Percent
1991	16.172
1992	16.344
1993	16.303
1994	16.861
1995	17.617
1996	17.439
1997	17.465
1998	17.215
1999	17.506
2000	18.078
2001	17.692
2002	18.397
2003	18.837
2004	20.301
2005	20.863
2006	21.845
2007	22.698
2008	22.75
2009	23.361
2010	23.833
2011	25.334
2012	26.054
2013	25.569
2014	25.787
2015	25.791
2016	25.676
2017	25.75
2018	25.895
2019	26.083
2020	26.277
2021	26.431
2022	26.548