After a scoreless first quarter, the Steelers drew first blood as Ben Roethlisberger connected with Rashard Mendenhall for a 13-yard catch for a TD to take a 7-0 lead.  With 0:06 left in the first half, the Steelers increased their lead to 10-0 with a 20-yard field goal from Shaun Suisham going into halftime.  In the 3rd quarter, the Eagles responded with Michael Vick's TD pass to WR LeSean McCoy to shorten the lead 10-7 for the only score of that quarter.  The Steelers responded in the 4th quarter with Shaun Suisham kicking a 34-yard field goal to make the score 13-7.  The Eagles however took the lead with Vick hooking up with Brent Celek for a 2-yard TD pass as the Eagles moved ahead 14-13.  However, the Steelers were able to move down the field in the final seconds and capitalize their victory with another 34-yard field goal from Shaun Suisham as they went on to win the game 16-14. With the win, the Steelers improved to 2-2.  They would also increase their record at home to 2-0.
Question: How many more TD passes were thrown in the second half than in the first half?
Answer: 2