I believe the 12-16 number of damaged aircraft was from independent verifiers using satellite images.

Reports say the US military is estimating 16 damaged or destroyed aircraft so far, possibly up to 20+ depending on confirmation from more satellite images and other intelligence sources.

Then again, similar to their vehicle storage facilities, many of the parked aircraft at Russian airbases are rusting hulks being cannibalized for spare parts.

Hopefully the UAF knew which ones were airworthy and damaged the aircraft that were actually capable of flying.