Year	%
1984	33.5
1987	31.4
1990	32.3
1993	33.2
1996	35.6
1998	32.2
1999	32.1
2000	29.5
2001	30
2002	32.8
2003	33
2004	33.9
2005	34.1
2006	35.3
2007	36.7
2008	36.1
2009	36
2010	37.2
2011	40.5
2012	40.5
2013	40.8
2014	40.2
2015	40.4
2016	39.3
2017	38.8
2018	38.4
2019	37.6
2020	37.6
2021	37.9
2022	37.9
2023	38.3