Answer based on context:

September 25, 2011 at Paul Brown Stadium, Cincinnati, Ohio (Blacked Out) Playing versus the San Francisco 49ers for the first time since 2003, the Bengals lost 13-8 with the smallest crowd for a Bengals home opener since 1981. Before the game, the team activated Simpson, who was previously injured. The only score in the first half was when Nugent kicked a 22-yard field goal in the first quarter. It took until 3 minutes left in the third quarter for another score, when 49ers' kicker David Akers tied the game with a field goal. The Bengals' final possession ended when 49ers' Reggie Smith intercepted Dalton's pass with 1:45 left in the game. It was Dalton's first performance where his passer rating was below 100; this game he completed 17 of 32 passes for 157 yards and a rating of 40.8. Coach Lewis claimed the lack of third-down conversions (1-10) were the main reason why the team lost, saying that "We are not converting the third downs or converting in the red zone, and we are not coming away with touchdowns. Right now, that is our biggest deficiency."

How many incomplete passes did Dalton have all game?
15