Peter Norvig has some interesting statistics on word frequency in the English language. It turns out that four words – the, of, and, to – account for 16.94% of the words we write.
In field of technical communication, Technical Authors typically spend 50% of their time writing and the rest on researching, planning etc. If we adjust for the fact that these four common words are half the length of an average word in English, that means Technical Authors spend an average of 19 minutes every day typing those four words. In a 37.5 hour week, that amounts to 1 hour and 35 mins.