It all depends how many units a day one is betting. ROI is a better indicator of what you want to know.
I would say if you make in the 2% range then you are doing very good at this.
In the past I have shot for around 20 units of profit (betting 1 unit a game) a month but this was with 1,000 units bet a month. No way someone is going to make 20 units a month betting only 200 1 unit plays a month as that would be 10% ROI and overtime that would be impossibile.
Wow, 20 units per month! Doing some quick math, that equates to 240 units a year on average. So if your unit size is let's say $500, then you can make about $120,000 per year. This seems awfully high to me, but I'm not doubting you Iceman. What percentage of people do you think can actually achieve this level?
Why are you assuming the average unit is $500?
I was just proposing an example to work through the numbers. I'm not saying that most people have the bankroll to bet this high.
I still think 120 units a year seems really high. I was thinking more like 70-80 units a year would be very successful for someone doing this full-time. I do agree that it really depends on how you go about this - whether you're capping all of the games or just simply looking for good numbers and pounding them.