The terms of service forbid us to say exactly what we earn on HP. We can say whether we make payout on a monthly basis and other vague stats. I have another account here with 29 hubs that does make monthly payout.
This forum thread may be useful to you. HP staff weighs in on what the top earners are making: http://hubpages.com/forum/topic/119588#post2531802
If you have not signed up for the Amazon affiliate program, you should do so as I think that is helping many hubbers make monthly payout.