Year	Percent
1991	57.875
1992	59.176
1993	56.863
1994	55.563
1995	54.829
1996	52.653
1997	52.204
1998	53.71
1999	53.35
2000	50.965
2001	50.537
2002	50.844
2003	50.45
2004	49.952
2005	52.547
2006	52.854
2007	52.652
2008	51.672
2009	50.746
2010	51.46
2011	50.604
2012	50.571
2013	50.332
2014	49.877
2015	49.457
2016	49.12
2017	49.074
2018	49.025
2019	48.975
2020	48.923
2021	48.87
2022	48.815