Year	% of total
1990	99.65557001905
1995	99.2324566196394
2000	98.6784258759277
2005	99.1482984298898
2010	98.4515418523421
2011	99.2571707780935
2012	97.4101430930591
2013	95.7683551530782
2014	93.7856719726694
2015	91.4744653522326
2016	85.0159346896433
2017	85.0515376653505