Year	% of total
1990	0.20517120248017
1995	0.101494373214372
2000	1.6950817361099
2005	1.74892391156435
2010	3.48966894370546
2011	1.80476948569318
2012	1.81303688677819
2013	1.82087016231344
2014	1.82818879816914
2015	1.83492450778168
2016	1.84105216138939
2017	1.84668337737681