What was the signed year for the Chinese name 蘇永康 who separated in 1987?
CREATE TABLE "list_of_male_capital_artists_singers" (
  "english_name" text,
  "chinese_name" text,
  "year_signed" real,
  "year_separated" text,
  "reason_for_separation" text
);
SELECT "year_signed" FROM "list_of_male_capital_artists_singers" WHERE "year_separated"='1987' AND "chinese_name"='蘇永康';