I would like to know, from people who have experience in producing soundtracks for cartoon TV series: what is the normal percentage of the total budget that is dedicated to music production?

I'll go with 'not enough'.

rogeriodec
I would like to know, from people who have experience in producing soundtracks for cartoon TV series: what is the normal percentage of the total budget that is dedicated to music production?

Check out the "Cartoon Music Book" for a huge history and more. 
 
It depends on the group and company, but for the most part the budget was not that big, but folks like Carl Stallings, could create a cartoon with 100 instruments in less than 5 minutes, and drive you nuts with it ... for a beer!
 
You don't want to discuss this on Disney productions ... it's the main reason why they lost so many cartoonists many years ago, and so many of them went on to be famous on their own, without Disney. The 2 books by Chuck Jones are highly recommended for reading, to give you an even better idea.
 
But the answer you don't want is ... no money! And then you gotta put up with things like ... Nasa ripped off Chuck Jones and his cartoonists ... they invented the rockets that Nasa used to send folks into space ... and never got a dime for it. 

Moshkito
 Nasa ripped off Chuck Jones and his cartoonists ... they invented the rockets that Nasa used to send folks into space ... and never got a dime for it. 

 
Yes, that must be true, because no-one had ever imagined a rocket before 1950.
 
Oh..except the Chinese in the 13th Century...and this guy...
 

Thanks, but maybe I should be more objective. For example, in a total project budget of $2 million, on average, how much for music? 5%, 10%, 20%, 50%?

Seriously, I don't think anyone here can answer that. Have you asked the producer what the budget is?

jamesg1213
Seriously, I don't think anyone here can answer that. Have you asked the producer what the budget is?

I know how much of the budget was dedicated to music in my project, but I'd just like to know if is this within the market average.

I did a quick search but couldn't find anything. Found this though, which might be of interest;
 
https://www.soundonsound....ques/cartoon-composing

We had someone here who wrote music for cartoons and, for the life of me, I can't remember who...  He was from Norway I believe.