What you are looking for is the wonderful site wordcount.orgwordcount.org. Enjoy.
About Wordcount Wordcount is a visualization of the way we use language. It presents the 86,800 most frequently used English words [...]
Wordcount data currently comes from the British National Corpus®, a 100 million word collection of samples of written and spoken language from a wide range of sources, designed to represent an accurate cross-section of current English usage. Wordcount includes all words that occur at least twice in the BNC®. In the future, Wordcount will be modified to track word usage within any desired text, website, and eventually the entire Internet.