Year	% of total
1990	84.3600427567836
1995	84.3958104633187
2000	83.7858271609562
2005	85.9058417688167
2010	85.6561026531686
2011	86.5338121117194
2012	83.5419690766864
2013	82.6774923236942
2014	81.5737124922405
2015	80.7197375513004
2016	76.5917479510371
2017	76.7171552248226