Did only SC/ST convert to Christianity during British Era?

It is often said that the Christianity has only converts from SC/STs, while the rest of the upper castes never converted to Christianity during British Era.

Was just going through the 1871 Madras census document. It gives a surprising account of various castes converted to Christianity.

Notice that in South Canara, more than 3697 Brahmanas became Christians.

Shanars of Tinnevelly, who are treated as Kshtraiyas, had more than 5100 Christians.

Similarly trading castes had 3819 christians ,of whom the greater part are in Malabar, Tanjore, Tinnevally.

Vellalars had 41889 Christians.

Vanniyars had 102263 Christians

However from the above analysis it is clear that all great caste divisions contribute to the Christian Community. However the numbers are highest amongst the lower castes.