Year	Percent
1991	66.865
1992	67.028
1993	67.894
1994	66.741
1995	67.221
1996	67.497
1997	67.064
1998	67.466
1999	66.858
2000	67.319
2001	66.347
2002	66.93
2003	65.503
2004	65.535
2005	65.303
2006	65.314
2007	65.054
2008	64.585
2009	63.91
2010	63.971
2011	62.821
2012	61.984
2013	61.74
2014	61.431
2015	60.932
2016	60.578
2017	60.304
2018	60.054
2019	59.796
2020	59.507
2021	59.226
2022	58.918