Year	%
1984	20.1
1987	20.5
1989	20.5
1992	20.6
1995	20.4
1997	20.3
2003	21.4
2006	21.6
2008	21.8
2011	21.8
2013	21.7
2015	22
2018	22.1
2021	22.1