I have been discussing the decrease in static wormhole numbers with dr. Fritte Cornelius from Signal Cartel.
The number is not always exactly thirty, but fluctuates. There appears to be a cycle, around noon it starts out low, rising to forty and close to fifty at midnight, then it decreases back down towards the next noon. This seems to imply human interference, rather than a natural phenomenon.
Dr. Cornelius has offered an interesting hypothesis that sounds correct to me. It is best to test it before it is made public, I think. That requires some experimentation that is not very easy to perform: an attempt to generate a wormhole in Sanctified Vidette ourselves, using the Sleeper Thermoelectic Convertors in known space.
These structures need to be scanned down. I stumbled on some abandoned ones in Sanctified Vidette; they look like this:
