How do you find out your ethnicity percentage?

Ok I consider myself black but my grandmother has told me that I'm mixed with quite a few things & I think I have a few mixed traits . I only go as far as great grandparents , my moms grandma is 50% white shes from Louisiana & would be considered(a black cajun) she speaks french & all that . My moms grandpa is also a black cajun from Louisiana as well . My moms dad is about 25% white & a mixture of cajun , black , & white . My moms mother is a black lady . My fathers great grandma was 25% cherokee indian , my dads family is also from Louisiana but his family is more french creole & I was told my dads family had some Haitian in their bloodline . So my question is what is my ethnicity percentages ? By the way , I do still consider myself to be black , I'm just curious to know .