Read this and answer the question. If the question is unanswerable, say "unanswerable".

Soon after the passing of the 1931 Act, in the book published on the occasion of the Institute's centenary celebration in 1934, Harry Barnes, FRIBA, Chairman of the Registration Committee, mentioned that ARCUK could not be a rival of any architectural association, least of all the RIBA, given the way ARCUK was constituted. Barnes commented that the Act's purpose was not protecting the architectural profession, and that the legitimate interests of the profession were best served by the (then) architectural associations in which some 80 per cent of those practising architecture were to be found.

When did the Royal Institute celebrate its 200th anniversary?
unanswerable