Which is the lowest 1980 growth that had 2,610 in 1970?
CREATE TABLE "population_growth_history" (
  "city" text,
  "1970" real,
  "1980" real,
  "1990" real,
  "2000" real,
  "2010_est" real
);
SELECT MIN("1980") FROM "population_growth_history" WHERE "1970"='2,610';