Pokémon Let's Go: What is the increased capture rate after capturing x amount of a certain Pokémon?

I've spent some time researching this, and have not been able to find hard numbers. My go-to source (serebii.net) only has this to say on the matter:

As you increase your catches of the same species of Pokémon, the capture rate will increase. This does not have to be within a combo. [Source]

Various forum threads discuss bonuses at 50 and 100 total captures. Anecdotal evidence seems very strong for the bonus at 100 captures, and less strong for the bonus at 50 captures.

https://www.reddit.com/r/PokemonLetsGo/comments/a0t40x/pokemon_becoming_easier_to_catch_not_tied_to/

https://gamefaqs.gamespot.com/boards/240025-pokemon-lets-go-pikachu/77232663#9