Has there been a national referendum since 1980?

Nohlen, D, Grotz, F & Hartmann, C (2001) Elections in Asia: A data handbook, Volume I, p534 ISBN 019924958

A constitutional referendum was held in Bangladesh on 15 September 1991. Voters were asked "Should or not the President assent to the Constitution (Twelfth Amendment) Bill, 1991 of the People's Republic of Bangladesh?" The amendments would lead to the reintroduction of parliamentary government, with the President becoming the constitutional head of state, but the Prime Minister  the executive head. It also abolished the position of Vice-President and would see the President elected by Parliament.

The result saw 83.6% vote in favour, with a turnout of 35.2%.