If you have as you say, 80 sites and earn 2-3$ from them, you must be doing something really wrong. Start producing quality stuff!
In my opinion, you should have only 2-3 sites, and you work hard in these sites about backlink, content, directory submissions, etc.
I'm not trying to be mean, but if you ave that many sites and are only making that much money, that says to me that you either have terrible sites with crappy content, or little to no SEO at all...or both. It also says that you have more sites than you can handle since none of them are doing anything. If you can't make money with 1 site, duplicating that failure just gives you more crappy sites. I'm speaking from experience. I used to have a ton of crappy sites that didn't make any money.
i know my first mistake was to many to fast. take like 3 or 5 and DO THEM RIGHT. then move on to the next bunch. you cant do 70 at once. you wont make a dime when your site is showing up on page 20 of G