Year	Percent
1991	24.07
1992	24.441
1993	24.551
1994	24.517
1995	23.632
1996	21.006
1997	20.671
1998	20.473
1999	23.907
2000	22.32
2001	21.792
2002	18.115
2003	20.168
2004	15.92
2005	16.971
2006	16.875
2007	15.626
2008	14.761
2009	13.808
2010	16.764
2011	18.289
2012	18.447
2013	17.199
2014	19.686
2015	19.238
2016	19.502
2017	19.594
2018	19.455
2019	19.26
2020	18.983
2021	18.648
2022	18.235