Anyone but Boeing know how many problems have occurred? Does it rise to the level of "incident"? Or does Boeing simply change out the charcoal remnants with a new battery, as they did, without reporting the failures, as before? Does it make it to the aircraft log? Certainly, right?
Lots of different ways "incidents" get reported. Not all are in the aircraft logs as the details may only become known afterwards.
In my experience the most thorough reporting both in quantity and validated facts are the reports from operator's maintenance operations directly to the manufacturer. Of course what tdracer said is true but there is a lot of leeway in what gets reported to the local FAA as "Service Difficulties and the level of valid facts makes it almost useless unless it was major enough to attract the attention of the Certificate office.
The fuse in all this is the FAA oversight of the airworthiness certificate holder (aircraft and engine manufactures etc.) data collection and actions under Continued Airworthiness. That data is far more useful in being proactive and is the support for the Service Bulletins that get passed around everyday. We simply look to the FAA to mandate compliance action as needed