Year	Percent
1991	27.95
1992	27.279
1993	27.095
1994	27.918
1995	28.966
1996	27.413
1997	27.574
1998	26.796
1999	27.16
2000	26.842
2001	26.852
2002	27.485
2003	27.797
2004	28.03
2005	28.448
2006	26.904
2007	25.992
2008	26.778
2009	26.825
2010	27.035
2011	25.796
2012	25.193
2013	24.563
2014	23.864
2015	23.516
2016	22.468
2017	22.373
2018	22.151
2019	21.962
2020	21.753
2021	21.479
2022	21.205