The Pew Research Center on Christian Sermons in America
The Pew Research Center has published some very interesting finds about Christian sermons here. The data examined the transcribed texts of 49,719 online sermons from 6,431 churches preached between April 7 and June 1, 2019. The findings conclude that,
Sermon length varies across religious traditions,
Sermons share common language, but some terms are distinctive,
Most sermons mention books from both Old and New Testaments,
Smaller churches are more likely to cite books of Old Testament by name.
The article includes helpful visuals such as this one.