Year	Percent
1991	26.626
1992	26.616
1993	26.616
1994	26.256
1995	25.979
1996	25.5
1997	25.191
1998	25.666
1999	27.069
2000	26.643
2001	28.07
2002	28.244
2003	27.06
2004	24.839
2005	25.886
2006	26.282
2007	27.637
2008	28.044
2009	28.525
2010	28.993
2011	30.063
2012	29.966
2013	31.498
2014	31.355
2015	32.625
2016	32.73
2017	33.198
2018	33.297
2019	33.484
2020	33.683
2021	33.881
2022	34.077