Year	% of total
1990	84.7913792600013
1995	83.5780694565578
2000	76.768307198207
2005	74.1580218099126
2010	72.5179891811153
2011	74.5372110296372
2012	70.7584704383753
2013	70.7237473663965
2014	70.0747372290815
2015	70.3269443454513
2016	64.198824466865
2017	63.6052640467056