Usually I get one decent one per year. On Fm10, one time I had two really good ones and one was American (I was Sporting CP, so it was a pleasant surprise), so I was really excited, and then the computer crashed and I lost it. I was so ******. I re-loaded the save and got all ****** regens. So I decided that I'd re-load it 5 times and pick the best one. On the 5th try I got an absolutely world class regen. I've never gotten a really good one before, but this guy might be the best in the history of all regens. But I did a poor job on the training (wasted it all on attacking and shooting, which he was already almost on 20 for many of the attributes) and not nearly enough on aerobic, so he ended up with only 14 for pace...other than that he was pretty much perfect. 20 for a lot of important ratings, and all the important ones were 16 or above.
Point of the story is it's total luck. If you want to cheat, save right before they re-generate and keep loading til you get a good one. It's definitely cheating though and I felt really guilty about mine, even though I didn't think I was cheating.