Year	Percent
1991	37.23
1992	37.506
1993	37.711
1994	37.783
1995	37.645
1996	37.958
1997	38.083
1998	38.048
1999	37.942
2000	37.851
2001	38.08
2002	38.241
2003	38.361
2004	38.438
2005	38.475
2006	38.823
2007	39.042
2008	39.18
2009	39.28
2010	39.362
2011	39.681
2012	39.902
2013	40.022
2014	40.024
2015	39.895
2016	39.869
2017	39.964
2018	40.052
2019	40.146
2020	40.252
2021	40.374
2022	40.504