Year	% of total
1990	77.3224993736826
1995	76.0300657460127
2000	82.3732253962654
2005	82.5698559528329
2010	83.4910349833979
2011	83.7958479336847
2012	81.7794455647145
2013	81.6110722754935
2014	73.6538225251846
2015	74.8305766714314
2016	63.3316924348098
2017	63.3960830638209