RCA(i) = [(Wales’ exports of good i to world)/(Wales’ exports of all goods to the world)]/ [(World’s exports of good i to world)/(World’s exports of all goods to the world)]
RCA(i) [(Allforion Cymru o nwydd i i’r byd)/(Allforion Cymru o bob nwydd i’r byd)] [(Allforion y Byd o nwydd i i’r byd)/(Allforion y Byd o bob nwydd i’r byd)]