Year	Percent
1991	46.084
1992	42.773
1993	47.657
1994	48.957
1995	57.815
1996	64.045
1997	62.093
1998	58.054
1999	57.194
2000	54.675
2001	55.77
2002	56.502
2003	52.546
2004	51.294
2005	51.286
2006	49.37
2007	51.043
2008	47.68
2009	43.285
2010	41.162
2011	40.447
2012	40.894
2013	47.145
2014	46.417
2015	43.816
2016	42.146
2017	42.054
2018	42.156
2019	42.661
2020	42.571
2021	42.411
2022	42.731