I did some searches about it and I noticed that earnings vary from a photographer to another.
Some say they are earning $1000/month.
While some say they earned $121 from 60 image sales.
I haven't sold any as I just started but I'll be sharing about my earnings when I got one 😁 hopefully soon!
The stock photography market is only getting worse by the month. But generally the more you have uploaded the more likely you are to earn anything at all. Also depends on the subject and location, from my experience industry sell the most and earns the most. Also editorial images of events in cities: people walking in the rain or something similar. Bonus points for capturing big touristic locations within them. Things that newspapers/media are going to be searching for, basically.