WHAT to type, though? Sure, if you were typing like a typist from a manuscript, this would be a piece of cake. Most of us have to think (maybe plan) and work through the story as well.
I do take dictation from my characters, and when I am in the "flow state" as it were, I write very fast. Sometimes, unfortunately, the characters are obstinate and refuse to talk, or worse, they move about on the "stage" like puppets. Very passive-aggressive creatures, and that's when I know that I have not been listening to them or capturing their story the way they intended me to.