Complex sentence: In 2015, the fee for renunciation of U.S. citizenship was raised by 422% from US $450 to $2,350 and is the highest fee for the renunciation of a citizenship worldwide.
Split into simpler sentences: In 2015, the fee for renunciation of U.S. citizenship was raised by 422%. It went from US $450 to $2,350 and is the highest fee for the renunciation of a citizenship worldwide.