Name the total number of founded for yankton
CREATE TABLE "active_institutions" (
  "school" text,
  "location_s" text,
  "control" text,
  "type" text,
  "enrollment_spring_2012" real,
  "founded" real,
  "accreditation" text
);
SELECT COUNT("founded") FROM "active_institutions" WHERE "location_s"='Yankton';