Year	Percent
1991	40.341
1992	40.38
1993	38.892
1994	38.403
1995	37.732
1996	37.142
1997	37.658
1998	37.193
1999	36.597
2000	36.58
2001	36.133
2002	37.024
2003	37.535
2004	38.066
2005	38.625
2006	39.332
2007	40.612
2008	40.375
2009	37.845
2010	39.433
2011	40.811
2012	42.59
2013	38.822
2014	38.021
2015	39.505
2016	40.537
2017	40.946
2018	40.092
2019	39.866
2020	39.715
2021	39.604
2022	39.524