Year	Percent
1991	29.705
1992	29.774
1993	31.165
1994	29.741
1995	29.351
1996	29.131
1997	28.196
1998	27.8
1999	27.554
2000	27.623
2001	28.17
2002	28.431
2003	26.55
2004	25.76
2005	25.395
2006	24.498
2007	23.773
2008	23.822
2009	24.174
2010	24.517
2011	24.309
2012	23.804
2013	24.8
2014	25.131
2015	25.172
2016	25.051
2017	24.928
2018	24.858
2019	24.795
2020	24.751
2021	24.707
2022	24.672