Avg interest rate, total interest-bearing debt

How it's calculated. Monthly official average; changes once a month.

Source. Treasury, Average Interest Rates on U.S. Treasury Securities, official as of Sep 30, 2026.

* Per person (projected population) divides by the US population projected to now: the official Census Vintage 2025 estimate for July 1, 2025 (341,784,857), projected forward at Census's stated growth rate (343,051,422 at build time). Per tax return filed divides by 162,754,810 individual income tax returns filed in FY2025 (IRS Data Book, Table 1-2); a joint return counts once and returns with zero tax liability are included.