Question: This year, the percentage of our female users is 5%, we estimate this percentage will be 7%, 9%, 11%, 13% for the following years.

Can we say "This year, the percentage of our female users is 5%, we estimate this percentage will increment 2% every year."?

How could I make it clear that it is not `5%*(1+2%)`, `5%*(1+2%)*(1+2%)`, `5%*(1+2%)*(1+2%)*(1+2%)`, etc.?

And what if one wants to say the estimation is `5%*(1+2%)`, `5%*(1+2%)*(1+2%)`, `5%*(1+2%)*(1+2%)*(1+2%)`, etc.?

Answer: 
If you mean that the number of female users will increase by 2% of the original number every year, then yes, you could say:

> 
> We estimate that this percentage will increase1 by 2% every year.
> 
> 
> 

However, that is rather ambiguous. The following would be clearer:

> 
> We estimate that this percentage will increase by two points every year.2
> 
> 
> 

(Merriam-Webster defines ["percentage point"](https://www.merriam-webster.com/dictionary/percentage%20point) as "one hundredth of a whole : PERCENT".)

If you mean that the number will increase by 2% of the new value every year, then you could say:

> 
> We estimate that the number of female users will increase at a rate of 2% per year.
> 
> 
> 

Neither of my suggestions is entirely unambiguous, but most people will understand them as I've indicated. You could be even clearer at the expense of concision, but I assume that you don't want something too lengthy.

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1The verb "increase" is more common than "increment".  

2As in [John Gordon](https://english.stackexchange.com/users/173463/john-gordon)'s (now deleted) comment.
To avoid the ambiguity you refer to, I would say:

> 
> "This year, the percentage of our female users is 5%, and we estimate that this percentage will increase 2% every year, i.e. 5%, 7%, 9%, etc."
> 
> 
> 

If in fact you estimate 5%, 5 × 1.02%, 5 × 1.02 × 1.02%, 5 × 1.02 × 1.02 × 1.02%, etc. then I would say:

> 
> "This year, the percentage of our female users is 5%, and we estimate that this percentage will increase 2% exponentially every year, i.e. 5%, 5.1%, 5.202%, etc."
> 
> 
> 

(In the first case, you could say "... will increase 2% additively every year..." but the word "additively" is a bit extra, i.e. unnecessary.)