Year	%
1986	47.8
1989	50.5
1992	51.4
1996	47.4
1997	48.9
2000	51.5
2001	50
2002	49.7
2003	52.1
2004	52.1
2005	50
2006	52
2007	48.9
2008	48.1
2009	48.9
2010	47.3
2011	47.7
2012	46.1
2013	47.7
2014	44.3
2015	45.2
2016	45.7
2017	42.2
2018	43.7
2019	41.9
2020	39.6
2021	38.5
2022	37