What is the minimum number of members Europe had at the time Africa had 7375139?
CREATE TABLE "chronology_of_worldwide_membership" (
  "year" real,
  "worldwide" real,
  "africa" real,
  "america" real,
  "asia" real,
  "australia" real,
  "europe" real
);
SELECT MIN("europe") FROM "chronology_of_worldwide_membership" WHERE "africa"=7375139;