The number of special elections to each meeting of Congress has steadily increased over the past twenty years, from an average of 7.6 special elections in the five meetings beginning in 1993, to 11.6 in the five meetings starting in 2003, and to 13.4 in the five meetings that began in 2013 and ended in 2022.
| Meeting of Congress | Years | Average number of all special special elections per meeting | Average number of U.S. House special elections per meeting |
| 113-117 | 2013-2021 | 13.4 | 11 |
| 108-112 | 2003-2012 | 11.6 | 10.2 |
| 103-107 | 1993-2002 | 7.6 | 6.2 |
A meeting of Congress spans the period of time between two-year election cycles for the full U.S. House and one-third of the U.S. Senate. Each meeting of Congress typically has two sessions, one in each calendar year, as the Constitution requires that Congress meet annually.
