Year	%
1986	52.4
1989	55.5
1992	56.5
1996	52.7
1997	53.7
2000	56.2
2001	55.2
2002	54.4
2003	57.1
2004	57.1
2005	55.3
2006	57
2007	54.4
2008	53.6
2009	54.6
2010	52.9
2011	53.2
2012	52
2013	53.6
2014	50.2
2015	51.1
2016	51.5
2017	48.9
2018	50.1
2019	48.6
2020	46.5
2021	45.7
2022	44