Probability of hitting a flush from flop to turn

[Maverick511]

I know in holdem if you have four to the flush on the flop, you have a 19% chance to hit your flush on the turn and a 19.5% chance to hit it on the river. However if you are all in on the flop, you have a combined 35% chance to hit it from flop to river. Can anyone show me the math used to calculate the 35%??


Thanks
-=Maverick=-