Logarithmic or linear growth of attributes?

Wondering if anybody here might know, in RTTS when you gain more allies (friendlies, bros), is the growth of your attributes linear or logarithmic relative to the number of allies you have?

Linear seems like it would be unrealistic, unless other limiting factors are in place to keep it real.

I'm guessing logarithmic. Attributes take a lot longer to increase as you go higher.