Not nearly enough. I'm a college student so around 4-6.
Over the breaks (and hopefully when I graduate and get a full time job instead of balance homework, jobs, organizations, job interview, etc. ) I get a full 8-9 (which is what you're supposed to get for health reasons) and I can definitely feel the difference. I'm a lot more energized, I'm able to work out harder, and my skin is a lot more clear.