It varies from company to company, and it's also contingent upon equipment type, route structure, and seniority.

At XJT depending on the above factors, you could fly as much as 7 hours a day (scheduled of course) split into 3 to 5 legs max. It's also not unheard of for people to max out in a year (1000 hours as prescribed by the regs). I would say the average ranges between 700-800 hours, once you factor in vacations (we actually get to take ours).