Year	Percent
1991	22.948
1992	24.221
1993	22.645
1994	23.209
1995	20.872
1996	19.201
1997	19.107
1998	19.794
1999	20.286
2000	21.884
2001	22.442
2002	22.373
2003	23.263
2004	23.893
2005	24.583
2006	24.877
2007	25.442
2008	25.874
2009	25.706
2010	25.563
2011	26.053
2012	26.625
2013	27.009
2014	28.522
2015	29.003
2016	29.36
2017	29.188
2018	29.244
2019	29.285
2020	29.302
2021	29.308
2022	29.368