Harvard, MIT, Encyclopedia Britannica, The New Heritage Dictionary, and Google participated in a study of various n-grams in various languages in Google's book collection. Google has scanned approximately 15 million books into its freely available books database. Approximately 5 million of those books have good meta data and were used for the study at Harvard. Many interesting results came out of the study. The engineers at Google were so intrigued that they put up an n-gram search utility. You may enter any word of phrase to see how often it occurs as a percentage over any date range.
Here is a link to an n-gram search on the phrase: Catholic Church
(ngrams.googlelabs.com/ngrams/graph?content=catholic+church&year_start=1700&year_end=2008&corpus=0&smoothing=4) from 1700 to 2009 AD, which shows that interest in the Catholic Church as reflected by the database sample increased steadily from approx. 1720-1830, plummeted in the 1830's, rose sharply in the 1840's, then plunged sharply from 1840-1880, finally continuing to decline gradually from 1880 to the present.
1998-2008 shows an increase in popularity of the phrase: Catholic Church, as can be observed in this graph: