My top 100 domains (almost all portuguese) made $439.00 last month(wich was fairly average month)
Not a stellar performance perhaps but way more then before, ie 3-5 years ago.
If I have total of 500 domains, its enough to renew.
I also have one idn site developed as test (
dedetização.com) which is doing great job as far as indexing and ranking but is more like a hobby for the future use, perhaps.