The population has 'swelled/swollen' in recent years.
a 'swollen' ankle/gland
a 'swollen' river
(..) Peeta. Peeta! Peeta! Get off! Get off of her! Let go! No, Katniss. No, you're swollen. Don't touch. No, no, no. Calm down. Calm down. You're okay. Tell her she's awake. - Pee... - Don't try to talk. (..)2014 The Hunger Games: Mockingjay - Part 1