How big is the Internet?

Researchers have complained for years about the lack of good statistics about the internet for a couple fo decades, since the end of NSFNET statistics. What are the current estimates about the size of the Internet, all IP networks including managed IP and private IP, and all telecommunications including analog voice, video, sensor data, etc? CAIDA, ITU, Telegeography and some vendors like Cisco have released forecasts and estimates. There are occasional pieces of information stated by companies in their investor documents (SEC 10-K, etc).