Year	%
1990	25.8
1993	26.6
1996	27.3
1999	29.4
2002	31.4
2005	30.9
2008	32
2010	32.6
2011	31.8
2012	31.5
2013	30.3
2014	29.7
2015	29.4
2016	29.4
2017	29.9
2018	29.4
2019	29.5
2020	29.4