After a tough loss at home to the Lions, the Eagles traveled down south to New Orleans to take on the Saints in the Mercedes-Benz Superdome.  The Saints scored first with Patrick Robinson returning a Michael Vick interception 99 yards for a touchdown and a 7-0 lead for the only score of the game.  The Eagles got on the board in the 2nd quarter as Alex Henery kicked a 22-yard field goal to cut the lead to 7-3 not long before Chris Ivory ran for a 22-yard touchdown to move the Saints ahead by 11 with a 14-3 lead and then they would score again with Drew Brees finding Marques Coltson on a 1-yard touchdown pass for a 21-3 halftime lead.  The Eagles scored 10 unanswered points in the 3rd quarter with Vick hooking up with DeSean Jackson on a 77-yard touchdown pass for a score of 21-10 and then Henery kicked a 37-yard field goal for a score of 21-13.  But the Saints scored one last time as Brees found Jimmy Graham on a 6-yard touchdown pass for a 28-13 lead which would be the final score of the game as neither team scored in the 4th quarter.
Question: How many more points did the Saints score in the first half compared to the Eagles?
Answer: 18