Switzerland Imports of pebbles, gravel, flint, macadam of slag, tarred macadam from Oman was US$141 during 2018, according to the United Nations COMTRADE database on international trade. Switzerland Imports of pebbles, gravel, flint, macadam of slag, tarred macadam from Oman - data, historical chart and statistics - was last updated on May of 2024.