All data has been derived from the transcriptions in the IGI derived from the official 1911 transcription - thus it is a transcription of a transcription of an earlier transcription !
Based on various Church, Civil and, post 1821, Decennial Census data
The 1792 head count has been given as 512 in several publications - certainly as far back as Quayle's 1812 Agricultural Report where he quotes an 1810 Agricultural Report as source - not immediately clear what this is, there was an 1808 Report of the Agricultural Society in the Isle of Man published as part of its parent Workington Agricultural Society Rules and Report of that year (still to be checked) A figure of 612 would however better fit..
Santan is the smallest parish - several years had no marriage noted.
Several epidemic peaks can be noted - the 1837 in particular. The mid 1860's peak is due to use of Oatlands as a temporary lunatic asylum.
R.A. Houston The Population History of Britain and Ireland 1500-1750, Macmillan Education Studies in Economic and Social History (ISBN 0-333-56564-9) 1992