How many centerfolds were in the 9-98 issue?
CREATE TABLE "table1_1566850_9" (
  "date" text,
  "cover_model" text,
  "centerfold_model" text,
  "interview_subject" text,
  "20_questions" text,
  "pictorials" text
);
SELECT COUNT("centerfold_model") FROM "table1_1566850_9" WHERE "date"='9-98';