Year	Percent
1990	42
1991	42.01
1992	41.94
1993	42.06
1994	42.25
1995	42.3
1996	42.4
1997	42.44
1998	42.42
1999	42.41
2000	42.39
2001	42.38
2002	42.37
2003	42.35
2004	42.33
2005	42.31
2006	42.26
2007	42.2
2008	42.17
2009	42.13
2010	42.08
2011	42.11
2012	42.16
2013	43
2014	43.87
2015	43.97
2016	44.02
2017	42.64
2018	42.92
2019	42.97
2020	41.34