Year	%
1991	54
1995	49.9
1996	51
1998	54.5
1999	52.2
2000	51.5
2001	51.4
2002	51.9
2003	50.5
2004	47.8
2005	48.5
2006	45.7
2007	45.2
2008	46.9
2009	45.8
2010	43.5
2011	42.3
2012	41.8
2013	43.4
2014	41.6
2015	40.6
2016	40
2017	38
2018	38.6
2019	38.8
2021	39
2022	38.8