Bhutan Exports of bitumen and asphalt (natural), bituminous or oil shale, tar sands to Hong Kong was US$73 during 2018, according to the United Nations COMTRADE database on international trade. Bhutan Exports of bitumen and asphalt (natural), bituminous or oil shale, tar sands to Hong Kong - data, historical chart and statistics - was last updated on February of 2026.