The Steelers went back home for a Thursday Night duel against the Titans. In the first quarter, the Steelers scored first when Ben Roethlisberger found Antonio Brown on a 41-yard pass to make it 7-0. They would make it 10-0 after Chris Boswell nailed a 41-yard field goal. The Titans got on the board later on in the quarter when Marcus Mariota ran for a 7-yard touchdown, making it 10-7. In the second quarter the Steelers pulled away as Boswell kicked 2 more field goals from 28 and 50 yards to make the score 13-7 and then 16-7 at halftime. In the third quarter, the Titans came within 2 when Mariota found Rishard Matthews on a 75-yard pass, making it 16-14. The Steelers would pull away again as Roethlisberger and Brown connected on a 5-yard pass, making the score 23-14. The Titans came within 6 later on when Ryan Succop kicked a 44-yard field goal to make it 23-17. In the fourth quarter, it was all Steelers as they sealed the game when Roethlisberger found Jesse James on a 1-yard pass to make it 30-17. This would be followed by Roethlisberger and Brown connecting on a 10-yard pass to make it 37-17. Boswell then finished with a 26-yard field goal to make the final score 40-17. With the win, the Steelers improved to 8-2, and enjoyed the best 10-game start of Mike Tomlin's career, and the best 10-game start for the Steelers since 2004 when they began 9-1. The victory marked the first time since 1984 that the Steelers defense forced at least 4 turnovers and 5 sacks in the same game. Their plus-4 turnover ratio was the first time this was accomplished by the Steelers since November 24, 2013 against the Cleveland Browns.
Question: How many points were the Steelers leading by at halftime?
Answer: 9