Does anybody have statistics for assigned-but-not-announced space? I'd be willing to bet there will be more and more dead space over the years, and in fact quite a bit of "increasing usage" is just churn. I have these statistics at http://www.completewhois.com/statistics/ip_statistics.htm
At above page look specifically at the blue part of the graph for assigned- but-not-allocated space. I actually looked at opposite (assigned & routed - this I named "routing utilization ratio") as way to determine efficiency of RIR policies. This ratio is very high for the new ARIN ip blocks (97%), but as you pointed above the churn is high for older blocks and only 42% of allocated space in 192/8 is actively routed. The ratios are in between around 60%-80% for other old blocks and these numbers both has to do with allocation policies that were not developed at the time and with churn due to dead companies. I have done analysis for different time periods, see: http://www.completewhois.com/statistics/rir_ratios.htm If you need data on exact amounts, you will need to do your own substraction use allocation statistics data from http://www.completewhois.com/bogons/data/allocation-statistics.txt and substract current use data from http://www.completewhois.com/bogons/data/data-bgp-announced/ipv4-activeblock...
Does anybody honestly think companies will commit the capex needed to implement IPv6? Not without additional benefits. We need either applications that are working a lot better at ipv6 or we may yet have to see ipv4 space ran out before it becomes clear to everybody that ipv6 is a must.
--- William Leibzon Elan Networks william@elan.net