Year	Percent
1991	25.319
1992	26.357
1993	27.266
1994	26.035
1995	21.606
1996	21.481
1997	20.173
1998	18.694
1999	17.466
2000	17.938
2001	17.94
2002	18.425
2003	20.486
2004	21.263
2005	20.792
2006	24.152
2007	25.162
2008	25.656
2009	25.125
2010	24.867
2011	24.997
2012	25.713
2013	22.914
2014	23.235
2015	23.848
2016	22.261
2017	22.314
2018	22.426
2019	22.51
2020	22.597
2021	22.621
2022	22.714