Single Table Sit N Go's

What's a good ROI% for 1-table, 8-handed, $5 SNG's with a 10% rake?

I've played 115 of these with a +3.3% ROI. That translates to $19 in profit over 115 tournaments.

Even if I jumped to $100 buy-ins with the same ROI, I'd have $380 in profit, which would translate to about $3-$4/hour

How does anyone make money in these things? Or are they designed for everyone to break even?