Question re: staking; I've been staking on and off for roughly a week but still haven't earned a single coin.  Granted, i am only staking with ~600PIVX, so I know it will take considerably longer.

What I am wondering is, does staking work based on cumulative hours/days?  Or consecutive?  If I stake for 6 hours and shut down my computer, I'm not likely to get anything, but did that time count toward some hidden figure?

Thanks!