The population of India during the British Raj days was first counted during the census of 1871. Prior to this a full census and data on British subjects were not available. The 1891 census also did a linguistic division, but nothing such as "British Subjects". But people who spoke English as a mother tongue returned 238,409.

The total Number of people with English as mother tongue, in India in 1891 as per the 1891 census was [238,409](https://archive.org/stream/cu31924023177268#page/n159/mode/2up).

The total Number of British subjects in India in 1921 as per the 1921 census was [165,485](https://archive.org/stream/cu31924014522746#page/n201/mode/2up).

The 1931 census was was the last census that was not subject to inaccuracies. The 1941 census was hampered by war and self-return from an illiterate populace.

> The European British subjects totalled 155,555 of whom 110,137 were
> males and 45,418 females. Of these again 7,205 males and 3,422 females
> were found in Burma, and while in Burma the figures show a total
> increase of 1,434 males and 1,365 females since 1921, the figures for
> India proper show a further fall since 1921 and are now little more
> than 80 per Cent. of those recorded in 1911, while males taken alone
> are fewer than in 1901.

Reference from [census record](https://archive.org/stream/CensusOfIndia1931/Census%20of%20India%201931#page/n437/mode/2up).