Year	Percent
1991	41.894
1992	42.55
1993	42.599
1994	42.195
1995	42.991
1996	41.82
1997	41.723
1998	41.613
1999	41.69
2000	41.48
2001	41.618
2002	41.596
2003	40.48
2004	40.682
2005	40.032
2006	40
2007	39.796
2008	39.903
2009	39.748
2010	39.177
2011	50.647
2012	37.929
2013	43.97
2014	47.182
2015	42.168
2016	41.599
2017	41.092
2018	40.948
2019	40.831
2020	40.626
2021	40.495
2022	40.411