There are many statistics about communication, the majority record pretty much the same results. The most famous compiled on effective communication was by a psychologist called Mehrabian. He found that in terms of impact during face to face meetings; the percentage is broken down as:

55% Appearance
How you look, your body language, the way you take up space.

38% The Message How you deliver the message. The tone, volume, pitch and pace speech.

7% Content What is actually being said.

So, 93% of impact has nothing to do with what you actually say!