CREATE TABLE "2011_preliminary_statistics" (
  "rank" real,
  "airport" text,
  "code_iata_icao" text,
  "total_cargo_metric_tonnes" real,
  "pct_change" text
);

Question: What is the highest rank for the airport with a code of HKG/VHHH?
SQL: SELECT MAX("rank") FROM "2011_preliminary_statistics" WHERE "code_iata_icao"='hkg/vhhh';