# Data Dictionary - US Treasury Average Interest Rates - coupon cost of the debt by security, cleaned

**Units:** stated per column in the descriptions below (this is a relational table; columns mix units).

| column | type | description |
|---|---|---|
| `month` | str | Month (YYYY-MM, with security_type + security the primary key) |
| `security_type` | str | Security type (Marketable, Non-marketable, Interest-bearing Debt) |
| `security` | str | Security (Treasury Bills, Notes, Bonds, TIPS, …) |
| `avg_interest_rate_pct` | float | Average interest rate (%) |

*Source: U.S. Department of the Treasury - Fiscal Data (Average Interest Rates on U.S. Treasury Securities).*