Year	Percent
1991	45.788
1992	43.215
1993	42.659
1994	40.753
1995	40.999
1996	40.871
1997	41.272
1998	41.269
1999	40.526
2000	41.008
2001	40.398
2002	38.158
2003	38.036
2004	38.412
2005	38.986
2006	39.988
2007	41.072
2008	43.094
2009	42.648
2010	41.835
2011	42.091
2012	41.989
2013	42.191
2014	41.958
2015	42.051
2016	43.361
2017	43.221
2018	43.051
2019	42.857
2020	42.662
2021	42.451
2022	42.285