1) According to national groups 2) Culturally 3) With respect to ethnicity 
• (adv.) In an ethnical manner.
Eth'nic·al·ly adverb In an ethnical manner. 
[adv] - with respect to ethnicity
ethnically With respect to ethnicity; such as, 'the neighborhood is ethnically diverse'. An ethnic group is a human population whose members identify with each other, usually on the basis of a presumed common genealogy or ancestry. Ethnic groups are also usually united by common cultural, behavioral, linguistic, or religious practices.
adverb with respect to ethnicity; `the neighborhood is ethnically diverse`