What is the sum of 1891(s), when 1872 is less than 685, and when 1881 is less than 348?
CREATE TABLE "population" (
  "1861" real,
  "1866" real,
  "1872" real,
  "1876" real,
  "1881" real,
  "1886" real,
  "1891" real
);
SELECT SUM("1891") FROM "population" WHERE "1872"<685 AND "1881"<348;