Source: here.
I have seen a bunch of estimates by Kashikar et al, Kannan and via various personal contacts. Drawing from all of them I come up with some numbers. These numbers can only be considered the rough lower bound
Tamil Nad (smArta-s and srI-vaiShNavas): 145 (found also secondarily displaced to Kashi e.g. Purushottama Dravid, a great soma ritualist)
Kerala (nambUthiris): 125
Karnataka (mainly havayaka and some tulavas): 50
Andhra (mainly vaidIki smArta-s): 160
Maharashtra (deshashtha, konkaNastha and karhADe): 100 (more than half for them live outside mahArAShTra in Kashi); Maharashtra also had the only shUdra who had performed a shrauta ritual in recent memory.
Rajasthan (brAhmaNa-s and kShatriya-s): 10 (Rajasthan is the only place were royal AhitAgni-s existed until recently. Some brAhmaNas of Rajasthani origin live in Kashi)
Himachal: 3
Gujarat: 3
UP (mishra-s and other native UP brahmins): 8
Some say that the greatest modern ritualist is the Andhra smArta: Renduchintala Venkatachala Yajulu. He performed numerous extraordinary and rare rites. Amidst the smArta-s of my ethnic group Narayanaswami Dikshitar, also udgAtar, a clansman on my maternal side was the greatest recent performer of rare and complex yAga-s.
We provide a normalized table below using the approximate estimates of V1s per state:
| STATE | # | N/10^6 |
|---|---|---|
| West Bengal | 2 | 0.27 |
| Uttaranchal | 3 | 0.74 |
| Gujarat | 8 | 1.47 |
| Delhi | 3 | 1.78 |
| Rajasthan | 10 | 1.82 |
| Himachal Pradesh | 5 | 3.64 |
| Uttar Pradesh | 95 | 4.32 |
| Maharashtra | 100 | 8.89 |
| Karnataka | 50 | 20.45 |
| Andhra Pradesh | 160 | 37.83 |
| Tamil Nadu | 145 | 80.39 |
| Kerala | 125 | 212.60 |