SCHEMA:
CREATE TABLE table_27319183_5 (official_itv1_hd_rating__millions_ VARCHAR, official_itv1_rating__millions_ VARCHAR)
USER:
What was the official ITV1 HD rating in millions for the episode that had an official ITV1 rating of 8.98 million?

QUERY:
SELECT official_itv1_hd_rating__millions_ FROM table_27319183_5 WHERE official_itv1_rating__millions_ = "8.98"