Year	Percent
1991	25.347
1992	24.316
1993	23.088
1994	21.124
1995	26.759
1996	27.512
1997	26.3
1998	25.982
1999	25.531
2000	25.043
2001	24.229
2002	23.757
2003	23.769
2004	23.48
2005	23.013
2006	21.941
2007	20.904
2008	18.357
2009	19.26
2010	19.744
2011	14.933
2012	15.532
2013	13.552
2014	12.849
2015	11.4
2016	12.085
2017	12.047
2018	11.971
2019	11.753
2020	11.509
2021	11.233
2022	10.942