Year	%
1980	26.3
1985	26.7
1990	24.8
1993	26.6
1994	26
1995	26.9
1996	26.7
1997	26.3
1998	25.9
1999	25.5
2000	25.8
2003	24
2004	24.9
2005	24.3
2006	24.9
2007	25.6
2008	25.6
2009	25.9
2010	26
2011	25.9
2012	25.8
2013	25.9
2014	26
2015	26.2
2016	25.8
2017	25.4
2018	25.3
2019	24.9
2020	25
2021	24.7