ngrams.googlelabs.com
This site produces graphs tracing popularity of any word through the ages from a large database of books.
Obviously one of the first words I keyed in was "Bible"
http://ngrams.googlelabs.com/graph?content=bible&year_start=1150&year_end=2011&corpus=0&smoothing=3
Quite fascinating to see the peaks and troughs and relating the graph to history.
Sad also, to see the great decline from the late 1850's onwards, coinciding with Darwin's "Origin"
and again on the plus side, it is encouraging to see a rise in popularity in recent years.
