Year	Percent
1991	53.622
1992	54.526
1993	55.024
1994	55.395
1995	52.768
1996	51.024
1997	50.181
1998	50.017
1999	50.694
2000	48.891
2001	51.452
2002	49.145
2003	50.19
2004	49.12
2005	48.176
2006	48.446
2007	47.729
2008	45.615
2009	45.86
2010	47.926
2011	49.02
2012	49.545
2013	49.95
2014	51.43
2015	52.854
2016	52.631
2017	52.635
2018	52.581
2019	52.523
2020	52.418
2021	52.255
2022	52.042