Year	Percent
1991	26.805
1992	26.172
1993	26.013
1994	26.035
1995	26.386
1996	25.075
1997	22.685
1998	24.82
1999	23.993
2000	23.379
2001	23.522
2002	24.043
2003	18.675
2004	17.661
2005	20.283
2006	20.651
2007	18.826
2008	17.068
2009	16.654
2010	16.485
2011	16.266
2012	15.872
2013	16.502
2014	16.911
2015	16.879
2016	15.965
2017	15.894
2018	15.697
2019	15.585
2020	15.491
2021	15.389
2022	15.298