Asking here, as suggested above, one has to be skeptical about the veracity of the numbers that will be given, especially about their net income for the year. It is too revealing.
A better way to pose the question, because it is not all that revealing per individual, but has some value for benchmarking, is how much anyone earning serious money is making on a per hour of effort.
From reading BHW, it seems not all are full time IMers, but many supplement their job or business income with IM.
After all, our choice is either put more effort into IM, or into our other alternatives. Per hour is a good barometer to make that call by.