What is the rate of catching a shiny Froakie, Dragonite, and a Mewtwo in Pokemon go?

Question

Ultra balls didn't work that much, I only caught 1 shiny Pokemon with an ultra ball. Shiny Pokemons dissapear immedietly after 39 seconds I think. So I ask this question about catch rate.

Please answer as soon as possible!

Answer 1

Froakie is 20%

Dragonite is 5%

Mewtwo is 2%

Source

There seems to be no reason to believe that being shiny affects these odds.