MP3 uses a compression that uses less bytes when there is no sound. Since it's not know what bitrate and more you won't know until you do the work.

HOWEVER you could compress one CD with CDEX and multiple the result by 100 to get an answer.

The answer will be wrong but may be close enough for you to tell.

Of you could just download it at http://www.audiotreasure.com/indexKJV.htm
Bob