Since then, the term has been altered three times – mainly in times of international crisis. During the First World War it was extended to five years. In the early 1930s, it was pushed out to four years. This proved to be unpopular with the electorate and after the election of 1935, the term was reduced to three years again. It was extended to four years once again during the Second World War, but returned to three years afterwards. In 1956, the term of three years was 'entrenched' in the Electoral Act which means that it can only be changed by achieving a majority in a national referendum or by a vote of 75% of all members of Parliament.