Today (Friday) the captain of a United 777 ordered an emergency evacuation upon landing of the regularly-scheduled Shanghai-Chicago flight. Smoke had been reported in the cabin. The 270 so passengers and crew exited via the chutes. (separate thread on the subject)
That made me wonder -- how often does this happens? For example, how many United flights used the slides last year? I'm not going to read the FAA database - thought someone here might have an idea of how common -- or uncommon -- it is for airliners.