What is the 1987 value of the 1994 atp masters series?
CREATE TABLE "singles" (
  "tournament" text,
  "1984" text,
  "1985" text,
  "1986" text,
  "1987" text,
  "1988" text,
  "1989" text,
  "1990" text,
  "1991" text,
  "1992" text,
  "1993" text,
  "1994" text,
  "1995" text,
  "1996" text,
  "1997" text,
  "1998" text,
  "1999" text,
  "2000" text
);
SELECT "1987" FROM "singles" WHERE "1994"='atp masters series';