It's too early to tell, because it takes 4-5 years to say for sure if a startup has succeeded, and YC is only 3 years old.

I'd be happy if it was a third, and delighted if it was as high as 50%.

What I'd like to know is, what % need to succeed for you guys to turn a profit. I'm sure it's too early to tell that too, but do you have any guesses?

Depends on the definition of succeed. IPO or HR acquisition? If the former, 1%. If the latter, more like 20-30%.

Right, I'd be interested to see 10 years down the line how many successes fit into each category (and in between). Still, if you can remain in the black with just 30% ending in an HR acquisition that's pretty strong. Seems like you should easily accomplish profitablity.