Year	%
1987	17.9
1990	17.3
1992	17.9
1994	17.7
1996	18.2
1998	18
2000	18.7
2003	19.1
2006	19.6
2009	19.3
2011	19.3
2013	19.2
2015	19.6
2017	19.6
2020	19.7
2022	20.3