How many deaths did the eyar with exactly 6 hurricanes have?
CREATE TABLE "1870s" (
  "year" real,
  "number_of_tropical_storms" real,
  "number_of_hurricanes" real,
  "number_of_major_hurricanes" real,
  "deaths" text,
  "strongest_storm" text
);
SELECT COUNT("deaths") FROM "1870s" WHERE "number_of_hurricanes"=6;