Year	Percent
1991	87.706
1992	87.744
1993	87.36
1994	87.761
1995	88.082
1996	88.311
1997	87.502
1998	87.212
1999	87.937
2000	82.533
2001	75.058
2002	65.901
2003	55.187
2004	41.712
2005	40.019
2006	37.295
2007	34.917
2008	33.327
2009	31.596
2010	28.022
2011	35.497
2012	39.677
2013	45.242
2014	51.433
2015	56.676
2016	57.243
2017	65.606
2018	68.585
2019	62.812
2020	60.457
2021	59.773
2022	59.157