Year	Percent
1991	39.489
1992	36.104
1993	40.281
1994	45.364
1995	45.195
1996	48.317
1997	47.279
1998	44.778
1999	45.635
2000	42.992
2001	41.957
2002	41.881
2003	41.822
2004	42.616
2005	44.634
2006	43.275
2007	41.961
2008	40.73
2009	44.027
2010	44.431
2011	43.945
2012	43.929
2013	43.538
2014	42.662
2015	42.061
2016	42.095
2017	43.371
2018	43.64
2019	43.623
2020	43.081
2021	42.69
2022	42.126