Task: Question Answering
Input (English): Passage: Due to the Falcons' loss to the Buccaneers earlier that same day, the Panthers entered this game having already clinched their third straight NFC South title&#8212;becoming the first team in the 2015 season to clinch a playoff berth, as well as the first team to clinch their division that season. Led by Drew Brees and a determined defense, New Orleans fought hard all game, their defense recovering three Panthers turnovers- including the first returned extra point attempt for points in NFL history. In the end, Carolina needed a 4th quarter game-winning touchdown drive from the offense (including a 4th down conversion), and a last-second defensive stand to seal it. With the thrilling win, the Panthers became the 9th team in NFL history to start the season 12-0. They also matched their franchise record for most victories in a season. 
Question: How many other teams started 12-0 before the Panthers achieved that same feat? 
Answer type: Number 
Output (English): 8.