Answer the following question: Given the following passage  "In 1970 the country switched its currency from the Bermudian pound to the Bermudian dollar, which is pegged at par with the US dollar. US notes and coins are used interchangeably with Bermudian notes and coins within the islands for most practical purposes; however, banks levy an exchange rate fee for the purchase of US dollars with Bermudian dollars. Bermudian notes carry the image of Queen Elizabeth II. The Bermuda Monetary Authority is the issuing authority for all banknotes and coins, and regulates financial institutions. The Royal Naval Dockyard Museum holds a permanent exhibition of Bermuda notes and coins.",  answer the following question. Note that the answer is present within the text.  Question: Before 1970, what did Bermudians use to make their purchases?
Answer:
Bermudian pound