Year	Percent
1991	71.444
1992	71.279
1993	71.091
1994	70.874
1995	70.993
1996	70.077
1997	69.251
1998	69.203
1999	68.956
2000	69.587
2001	70.07
2002	69.444
2003	69.399
2004	70.31
2005	69.452
2006	69.476
2007	69.453
2008	69.024
2009	67.018
2010	66.264
2011	64.057
2012	60.951
2013	57.799
2014	57.066
2015	57.294
2016	59.156
2017	60.203
2018	60.627
2019	60.844
2020	60.937
2021	61.016
2022	60.987