Complex sentence: Beginning with the 2016 presidential election, Bulgaria introduced a'none of the above' option, which received 5.59% of the vote in the first round and 4.47% in the run-off.
Split into simpler sentences: Beginning with the 2016 presidential election, Bulgaria introduced a'none of the above' option. It received 5.59% of the vote in the first round, and 4.47% in the run-off.