Smaller one occurred during that time period, but the largest was the Cincinatti Riots in 2001. All totaled, it ended up costing $13 million+.
Not all protests end up in riots, as well. Take the million man March. Okay, a million men did not participate, but the National parks service initially estimated 400K men. It later adjusted that figure to 800K +, with a 20% margin of error. But it started as a peaceful March, and ended as such.
The main trigger in the race riots usually point to some abuse of power by law enforcement. If charged with a crime, the law enforcement officers are generally acquitted.