Thanks for the replies so far.
Don’t worry, I am not extrapolating from my observation to conclude it’s not always just a straight 20% chance of each color. I know my alliance experience of 8/21 at 4% will currently be shared by 1 in 25 alliances , probably 1000’s therefore.
I probably won that 5 % chance , instead of the one to pull a Zeline this month.
I was curious enough to crunch the numbers - mainly because so many yellows annoys Wu Kong , who’s in charge of my team ))) . It crossed my mind that different titan levels might have non-uniform color distribution though , like mammoths are always blue, but dragons I have seen different colors I think, and whether the RNG might select the type of titan first and then the color, if there was a choice, so skewing the color mix. If that makes sense - I have only seen 4/5 * titans since I have been playing so was not sure.
An equivalent scenario I think would be for summons,which order might the RNG choose by ? star first or color - at some points , depending on events etc , some colors may have more heroes at a particular level.