Ask HN: Which linux kernel versions are actively used in cloud computing?

I'm trying to find the market share of linux kernel versions in the cloud computing world. Not too interested in long tail, just top ones in the 80th or 90th percentile.

I've been trying to find the answer to this in various ways and came out empty handed: - Which AWS AMI's are most used? (90th %ile) - Which Linux distribution versions are most used?

Does anyone have good stats on this? (Or at least on one of the other proxy questions?)