Year	Percent
1991	35.741
1992	34.834
1993	33.467
1994	31.705
1995	29.779
1996	27.642
1997	25.191
1998	22.51
1999	22.172
2000	21.53
2001	20.237
2002	19.052
2003	23.375
2004	18.989
2005	21.15
2006	24.056
2007	23.115
2008	22.025
2009	20.639
2010	19.746
2011	19.384
2012	21.764
2013	20.263
2014	20.596
2015	19.466
2016	22.294
2017	22.325
2018	22.419
2019	22.528
2020	22.634
2021	22.727
2022	22.848