Year	Percent
1991	25.265
1992	25.43
1993	25.564
1994	25.402
1995	25.796
1996	26.019
1997	25.724
1998	26.687
1999	25.765
2000	25.122
2001	20.546
2002	22.895
2003	27.608
2004	27.674
2005	27.27
2006	24.303
2007	28.743
2008	27.042
2009	28.418
2010	28.285
2011	28.642
2012	27.688
2013	27.074
2014	28.76
2015	30.411
2016	30.653
2017	30.319
2018	30.516
2019	30.66
2020	30.814
2021	30.963
2022	31.077