Year	% of total
1990	21.6722676840399
1995	22.865439117169
2000	22.0786353058569
2005	24.3448830401953
2010	26.9115576797831
2011	23.9817600420236
2012	25.8553780777936
2013	27.3813001045066
2014	15.1763033237859
2015	4.68963262649578
2016	2.98614050990621
2017	3.15055011718451