Demographics of Poland
According to GUS, about 38,325,000 people live in Poland, however, the same report states that the number of residents living in the country all the time is approximately 37,200,000; with 1,125,000 people living abroad for 6 to 7 months or more. It means that the permanent population may be correspondingly smaller.
United States of Poland
Paderewski's idea postulated rebuilding a Polish state as federation, in which constitution and law would guarantee equality to citizens, ethnic and religious groups. Territory would engulf most of pre-partitioned territory. Taking into account of that time population, the country would have 54 million citizens. On its head would be a President with a title of the King of Poland, Lithuania, Polesia and Halych.