Don't forget about The Omega Directive, where she flat out tells Tuvok that the Prime Directive is rescinded. Though, I suppose you could cut her some slack there, seeing as how the Omega Directive does, in fact, over-ride the Prime Directive.
She broke the Prime Directive a number of times. However, this is the only time she flats out admits to doing so.
But she flat out admits to doing so because Starfleet protocol requires it, so I have a hard time counting that one.