Year	Percent
1991	41.069
1992	41.209
1993	40.95
1994	40.663
1995	40.53
1996	40.536
1997	40.67
1998	40.89
1999	41.132
2000	41.361
2001	41.51
2002	41.643
2003	41.763
2004	41.866
2005	41.953
2006	42.006
2007	42.042
2008	42.072
2009	42.107
2010	42.154
2011	42.196
2012	42.249
2013	41.913
2014	41.466
2015	40.922
2016	40.561
2017	40.645
2018	40.737
2019	40.835
2020	40.935
2021	41.026
2022	41.116