Percentage of available address space announced: 38.6
You misunderstand what IP addresse are. They have nothing whatsoever to do with the Internet. The address space announced on the Internet is an entirely separate issue. IP addresses were established as part of the development of a networking protocol called the Internet Protocol, or IP for short. This protocol was designed to allow many independent networks to interconnect or internetwork and exchange traffic. In order for such internetworks to work they need to be allocated unique IP addresses. The prerequisite for receiving globally unique IP addresses is that you have to be using IP technology and have a need to internetwork with other networks. There are several such IP internetworks that are entirely separate from the public (big I) Internet. That's where the other addresses are used and their usage is growing at about the same rate as Internet usage is growing. Think of it like Ethernet MAC addresses.
From where I sit, the perceived shortage is due to non-existant reclamation of unused resources,
It would be nice to see more reclamation and recycling of IP addresses. As near as I can tell, there is a fair bit of reclamation but it is all voluntary and ad-hoc. It isn't part of any publicly agreed process that would lead to reuse of those addresses.
All I see is that in 3-4 years we will actually have to engage our collective brains again and start getting new IP allocations from a different source.
If you agree with the Cisco IP Journal article then we have to engage our collective brains *NOW* to plan and test and be ready for the day when we need to do things differently. --Michael Dillon