I mean the intervals between population hitting a new billion (6B to 7B, 7B to 8B) They intervals have been getting shorter and shorter due to exponential growth. Obviously there will be a last such interval when population peaks (no 9B to 10B if we never hit 10B), but I would expect them to lengthen due to slowing growth rates (ex. 8 to 9 takes longer than 7 to 8) instead of the last interval being the shortest one (zoom from 7 to 8 at record speed and then never hit 9) I haven’t dived into specific rates and forecasts tho.