The Central Election Commission determined that 14 political parties could submit lists of candidates without collecting signatures. Whilst other parties were required to present at least 200,000 signatures (with a maximum of 7,000 signatures per region). Fourteen parties were registered to participate in the election. These are the same fourteen parties that did not have to collect signatures in order to participate. None of the parties tasked with collecting signatures were registered on the ballot due to various violations or failure to submit documents. In 225 single-member constituencies, candidates could be nominated by a party, or be self-nominated. United Russia won a supermajority of seats, allowing them to change the Constitution without the votes of other parties. Turnout was reported as low. Throughout the day there were reports of voting fraud including video purporting to show officials stuffing ballot boxes. Additionally, results in many regions demonstrate that United Russia on many poll stations got anomalously close results, for example, 62.2% in more than hundred poll stations in Saratov Oblast. This suggests that the results in these regions likely have been rigged. The government said there was no evidence of any large scale cheating. However, on 22 September the Central Electoral Committee canceled the results in seven constituencies, where the number of used ballots exceeded the number of registered voters, or where the authorities were videotaped stuffing the ballots. According to research by University of Michigan political scientists Kirill Kalinin and Walter R. Mebane, Jr., the election results are fraudulent. The breakdown of the party-list results by region is as follows: