Year	Percent
1991	54.183
1992	53.599
1993	53.787
1994	52.757
1995	52.6
1996	52.304
1997	52.048
1998	51.906
1999	52.064
2000	52.076
2001	52.021
2002	51.964
2003	51.611
2004	52.937
2005	49.139
2006	46.661
2007	46.2
2008	52.682
2009	53.737
2010	53.69
2011	53.652
2012	52.8
2013	52.653
2014	51.843
2015	51.814
2016	52.165
2017	52.12
2018	52.099
2019	52.027
2020	51.914
2021	51.786
2022	51.656