Year	Percent
1991	71.517
1992	70.809
1993	68.928
1994	67.479
1995	62.677
1996	63.285
1997	65.521
1998	66.495
1999	65.316
2000	64.799
2001	62.23
2002	60.058
2003	64.985
2004	66.606
2005	68.021
2006	69.287
2007	70.061
2008	69.681
2009	68.752
2010	69.081
2011	69.841
2012	69.589
2013	69.396
2014	68.704
2015	68.738
2016	67.437
2017	67.513
2018	67.611
2019	67.632
2020	67.261
2021	66.908
2022	66.598