Year	Percent
1991	23.941
1992	18.516
1993	20.189
1994	17.476
1995	22.725
1996	22.545
1997	24.165
1998	23.273
1999	23.491
2000	23.469
2001	22.865
2002	25.469
2003	25.203
2004	25.657
2005	26.477
2006	26.126
2007	25.834
2008	25.483
2009	25.865
2010	24.733
2011	23.995
2012	26.088
2013	26.473
2014	26.487
2015	25.677
2016	25.75
2017	25.97
2018	26.062
2019	26.04
2020	26.06
2021	26.103
2022	26.116