Passage: In 1969, the TEE service started with the Swiss designation CG, GC (Catalunya-Genève and v.v.) and the Spanish train numbers TEE 83,84. On 23 May 1971, the train was renumbered to TEE 70/71 – TEE 72/73; in Spain the numbers TEE 73,70 were used, from 26 May 1974 TEE 5073,5070. The double numbering is due to the fact that, in both terminals, outbound trains are given an odd number and incoming an even number. The original route was: Barcelona – Girona – Portbou – Cerbère – Perpignan – Narbonne – Béziers – Sete – Montpellier – Nîmes – Avignon – Valence – Romans Bourg de Péage – Grenoble – Challes les Eaux – Chambéry – Aix les Bains Le Revard – Culoz – Bellegarde – Geneva-Cornavin. On 31 May 1970, the stops at Romans Bourg de Péage and Sète were removed from the timetable.

Question: On what day and month of the year were the stops removed?
31 May 1970