Year	Percent
1991	51.425
1992	51.194
1993	50.165
1994	49.117
1995	48.046
1996	47.103
1997	46.155
1998	45.34
1999	42.819
2000	45.382
2001	46.058
2002	46.75
2003	47.45
2004	48.163
2005	48.876
2006	49.581
2007	49
2008	48.33
2009	47.735
2010	47.115
2011	47.896
2012	48.668
2013	50.109
2014	49.873
2015	49.6
2016	49.315
2017	49.195
2018	49.095
2019	48.991
2020	48.854
2021	48.703
2022	48.538