Looks like it’s right at 50% and rapidly increasing.
[https://www.google.com/intl/en/ipv6/statistics.html]
What exactly are you going on about? 5-10 years for the old devices to be EOL’d, and we’ll likely be at 95%.
The trend on that graph is slowing, and when we reach criticl mass on the number of mobile devices the graph will be flat.
There is no chance we will be at 95% usage in 5 years or so.
If you like, we can make a wager?
Devices maybe, software won't :-\ (We're going to see ever-diminishing pockets of IPv4 around for a loooong time, much like we still see pockets of Cobol.)