Year	% of total
1990	98.4995388808423
1995	98.4881162426444
2000	97.9996274895748
2005	98.3862339819715
2010	95.6533058710675
2011	93.143022136024
2012	91.1794332120876
2013	95.9648475971885
2014	96.4811543705689
2015	98.8077602122202
2016	98.7889501855133
2017	98.8200441196229