Clown Fish Raising

Hiya, im now in a position where i would like to start breeding my clownfish, Im just in the process of getting it all set up

My question is out of the eggs that are hatched roughly how many reach sellable size?

Before you say it all depends on how you care for them etc i just want to know how many you have raised out of one batch?
am i to expect 250 or 30 or even 1?

any help would be great

thanks

Dan