Bitcoin Price - The bitcoin price can be quite volatile at times at this can effect the mining payouts, good or bad.

Bitcoin Mining Difficulty - The mining difficulty can go up and down as more miners join and leave the network, this can also have a positive or negative effect on mining payouts.

You can also see historical data on the bitcoin network's mining difficulty at here:

You can also see independent data on the past mining difficulty changes here:

Did this answer your question?