Learn Portuguese (Portugal): O censo indica que dez por cento da população mora aqui. - The census indicates that ten percent of the population lives here.

In Portuguese, when a percentage is followed by a noun phrase like da população (of the population), the verb usually agrees with that noun. Because população is singular, the verb takes the singular form mora.

Could I use the plural verb moram in this sentence instead?

Yes, you can. Portuguese grammar allows the verb to agree either with the noun (população, which gives mora) or with the percentage number itself (dez, which gives moram). Agreeing with the singular noun is very common and sounds natural here.

If we removed da população and just said 'The census indicates that ten percent live here', how would that affect the verb?

If you drop the noun phrase, the verb must agree directly with the number in the percentage. Since dez (ten) is plural, the verb becomes plural: O censo indica que dez por cento moram aqui. If the percentage were um por cento (one percent), the verb would stay singular.

I have seen the word senso spelled with an s. Is censo a spelling variation?