Year	% of total
1990	41.7902976066106
1995	40.8709199460221
2000	43.1018598927466
2005	35.6315667810652
2010	34.4369028675816
2011	35.1983084859327
2012	37.0750035002077
2013	33.7469602416285
2014	33.4417386620577
2015	48.4068801790228
2016	45.1191538291513
2017	45.2199992457883