Year	%
1987	27.2
1994	29
1995	28.6
1996	27.6
2000	26.1
2002	25
2003	25.9
2004	26.6
2005	27
2006	25.6
2007	25.5
2008	24.6
2009	25.6
2010	24.9
2011	25.5
2012	25.9
2013	26.1
2014	24.9
2015	25.4
2016	25.9
2017	25.4
2018	25.1
2019	25.1
2020	23.8
2021	24.8