What was the official ITV1 HD rating in millions for the episode that had an official ITV1 rating of 8.98 million?
create table table_27319183_5 (official_itv1_hd_rating__millions_ varchar, official_itv1_rating__millions_ varchar, PRIMARY KEY (official_itv1_hd_rating__millions_))
select official_itv1_hd_rating__millions_ from table_27319183_5 where official_itv1_rating__millions_ = "8.98"