Year	Percent
1991	55.268
1992	53.872
1993	54.075
1994	53.146
1995	60.892
1996	57.271
1997	61.414
1998	68.035
1999	70.752
2000	77.41
2001	75.906
2002	67.713
2003	64.281
2004	70.157
2005	73.504
2006	74.407
2007	74.889
2008	73.821
2009	66.618
2010	65.501
2011	66.505
2012	68.403
2013	75.193
2014	73.221
2015	76.358
2016	78.266
2017	77.666
2018	77.619
2019	77.536
2020	77.462
2021	77.407
2022	77.378