Year	% of total
1990	74.4731017567561
1995	76.1039458849259
2000	82.4704783457187
2005	83.0533362291293
2010	83.6791054996014
2011	87.2897149888099
2012	78.3502768133659
2013	72.8615600436417
2014	64.7864638407275
2015	64.2831872399871
2016	55.6624227739091
2017	55.6219674748655