Accuracy of the Ranking Assumption

                Number of Errors

          President    Senate    House

2004          0
2008          1
2012          0
2014                     1/3
2016          3           2        3
2018                      2
2020         2.5          2

For the 2014 Senate election there were three betting markets used. For two there were no errors and for one there was one, so I used 1/3. For the 2020 Presidential election there was one tie, so I used 2.5.