I wouldn't be surprised if it was 90%. There were maybe one or two Chargers fans in our entire section, and the rest of the stadium didn't look much different. Parking lot was the same way. I am almost positive they were pumping in extra crowd noise whenever the Chargers had a big play, because there is no way that few people were making a full-stadium size cheer.
A few pictures I took, plus a video as people were filing out at the end of the game; look at the few lonely Chargers fans ...
https://vid.me/QyV4