Percentiles p25/p50/p75/p90 by inclusive interpolation.
Full-risk gap: share of cohort whose cost is below FEMA's full-risk premium.
Claims per 100: cumulative paid claims since 1978 over current policy units — a historical tally, not an annual rate or a flood probability.
Suppression: cost charts need ≥100 cohort policies; a ZIP page exists only if it passes the 3-part publish test (sufficiency, decision-relevant difference, distinct intent).
Dates: each figure shows its effective date and retrieval date; policy snapshot differs from other datasets' retrieval dates.
What the data cannot tell you
Your own premium (depends on elevation, coverage, deductible).
Private (non-NFIP) prices.
Your address's exact flood zone — use FEMA's Flood Map Service Center.