Year	Percent
1991	66.021
1992	65.738
1993	65.627
1994	65.866
1995	64.521
1996	63.703
1997	62.466
1998	61.549
1999	62.854
2000	64.979
2001	63.825
2002	63.352
2003	64.43
2004	62.822
2005	57.701
2006	52.64
2007	54.615
2008	54.508
2009	54.639
2010	52.207
2011	52.488
2012	51.293
2013	51.25
2014	51.832
2015	54.49
2016	54.105
2017	53.635
2018	53.562
2019	53.484
2020	53.403
2021	53.322
2022	53.238