Year	% of total
1990	99.18162550947558
1995	99.16280571626442
2000	99.22304640837115
2005	99.29225776224827
2010	99.22496564647189
2011	99.35732739657128
2012	99.16703209653862
2013	98.69999271782059
2014	98.250403548632
2015	98.2063394168371
2016	97.66835796737556
2017	97.65053891506781