Table: football_match_1999
Columns: home_team
home_team_score
away_team
away_team_score
ground
crowd
date
time

Question: What is the away team score for the match at 6:00 PM and an away team of Hawthorn?
SQL: SELECT "away_team_score" FROM football_match_1999 WHERE "time" = '6:00 pm' AND "away_team" = 'hawthorn'