The 2010 meeting between the Indianapolis Colts and the New York Giants marked the second time that the two quarterback brothers of Peyton and Eli Manning met in a football game, the last coming in 2006.  The game started out good early for the Colts with a running touchdown from Donald Brown and two separate stops by the defense against the Giants.  As the second quarter began the Colts kept rolling on the offensive side of the ball.  Two touchdown passes during the second quarter and a field goal from Adam Vinateri helped the Colts extend a halftime lead of 24-0.  With the start of the third quarter the Giants came out and scored early on a touchdown pass to Mario Manningham from Eli Manning.  With a 24-7 lead, the Colts continued to pound the Giants on defense, forcing a fumble which was returned for a touchdown.  The fourth quarter continued with a touchdown pass to Reggie Wayne while the Giants eventually scored their second touchdown in the last minutes of the quarter.  The Colts won the ballgame 38-14 ending their three-game regular season losing streak and improving their record on the season to 1-1.
Question: How many years ago two Manning brothers met in a game before 2010?
Answer: 4