Year	Percent
1991	27.076
1992	27.632
1993	27.661
1994	27.53
1995	27.044
1996	26.628
1997	25.884
1998	24.637
1999	24.561
2000	24.342
2001	24.554
2002	24.134
2003	24.066
2004	20.342
2005	20.359
2006	20.637
2007	20.229
2008	19.819
2009	19.614
2010	19.821
2011	20.881
2012	15.466
2013	14.099
2014	17.256
2015	17.712
2016	18.48
2017	18.534
2018	18.379
2019	18.236
2020	18.08
2021	17.932
2022	17.793