Are there any data for the whole "network luck"? I'm afraid those can't be obtained easily, because the whole network hashrate is calculated from found blocks, thus supposing "network luck" equal to 100 %. This way, one can't differentiate between hashrate changes and luck changes.
Or am I wrong?
On way of looking at it is that luck for the whole network is 100% all the time -- I mean, the network always finds a block. Another way of looking at it is whether the network is finding blocks in less than 10 minutes average per block (>100%), at 10 minutes average (100%), or longer than 10 minutes average (<100%), but then difficulty changes are used to keep the average as close to 10 minutes as possible.