Year	%
1970	29.73252
1973	28.74709
1974	29.05048
1998	97.21217
1999	98.20092
2000	97.69371
2001	97.39566
2002	96.5178
2003	96.70928
2004	95.86633
2005	95.38558
2006	94.96292
2007	95.16004
2008	95.31151
2009	95.87691
2010	96.17801
2011	96.62407
2012	96.84399
2013	97.31649
2014	97.40726
2015	99.48824
2016	99.85158