Here is a really interesting site.
Type in a keyword and Google will show the amount of searches for that word over a certain period of time. Certain religious terms like ‘church’ and ‘Jesus’ show a peak around April and March, the same time as Easter. Interest in both wains during the summer. ‘Evangelism’ produced another curious graph. Searches for evangelism have been falling since 2004 when the graph starts. Roughly every year around February and April or March is when the searches spike, with a steady slide through the rest of the calender year. Is the February rise caused by New Year’s resolutions to do more witnessing? All this speculation is terribly unscientific, yet a lot of fun. Try it for yourself.