It depends on niche. Your question would make more sense if you factored in niche, amount of effort, and methods of promotion
Wondering this kind of question will help you to improve your adsense earning? If not, no point to ask
Mine is an average of $2000 pm, even though I am from India. However, It took a long time to reach this level. It is possible, one of my friend from India gets around $30,000 to 40,000 pm.
I think the ONLY way to make $1,000's of dollars per month w/AdSense is to have some sort of website or forum like this one (digital point) that has 1000s of visitors per day. With just a few websites and a few articles here and there you'll be lucky to see $25/day - in my opinion.