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 register starts from 1626 - it would appear most Douglas baptisms were in the various chapels-of-ease.
The inexorable growth of Douglas is reflected here - the levelling off after 1780 reflects the licensing of St George's in Douglas for marriages, the older St Matthew's appeared to be shunned for this purpose.
Braddan New yard was opened in 1848 and is not included here; note the cholera of 1832 is small in comparison with 1837.
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