“Some 26 billion calls in 2018 were robocalls”
From: https://www.google.com/amp/s/techcrunch.com/2019/04/10/cybersecurity-101-robocalls/amp/
https://en.m.wikipedia.org/wiki/STIR/SHAKEN
STIR/SHAKEN, or SHAKEN/STIR, is a suite of protocols and procedures intended to combat caller ID spoofing on public telephone networks.