What was the Year to Open for the Dandeung Bridge?
CREATE TABLE "bridges_under_construction" (
  "name" text,
  "main_span_metres" text,
  "main_span_feet" text,
  "year_to_open" real,
  "country" text
);
SELECT COUNT("year_to_open") FROM "bridges_under_construction" WHERE "name"='dandeung bridge';