What it measures
SM is unitemized individual contributions (the FEC’s under-$200 field) ÷ all individual contributions.
By the numbers
| Measure | Value | Source |
|---|---|---|
| Small donors’ ($200 or less) share of all House candidates’ receipts, 1999–2000 | 15% | Campaign Finance Institute, Table 2-8 (House receipts by source) |
| Same, 2015–16 | 6% | Campaign Finance Institute, Table 2-8 (House receipts by source) |
| Same, 2017–18 | 12% | Campaign Finance Institute, Table 2-8 (House receipts by source) |
| 2020s cycles | data needed | not yet sourced |
CFI’s denominator is total receipts; ours is individual contributions, so card values run higher. Full formula: Methodology.