there are no formal rules for the allocation of seats, other than that no two judges may be nationals of the same country. in practice, the five permanent members of the united nations security council have each had a permanent seat on the court, except between 1967 and 1985 when there was no chinese judge and since 2018, when there has been no judge from the uk. the remaining seats have been informally allocated by regional groups in the same way as the fifteen seats on the security council. since 1970, the conventional allocation is three seats to asia pacific, three seats to africa, two seats to latin america and the caribbean, two seats to eastern europe and five seats to western europe and others. that convention was broken in 2018 when an asian judge was elected to a seat previously occupied by judges from the western europe and others group.