From Dec 2016 to Sep 2026 the index went from 146.6 to 176.7, a change of +20.5%.
Highest reading in that period: 344.6 in Oct 2021. Lowest: 60.5 in Apr 2020.
Largest one-month rise: +44.3% in Jan 2021. Largest one-month fall: -27.3% in Jun 2019.
For a clause that resets its base every year, a 10% cap or floor would have limited the adjustment in 27 of the last 36 months.
Use it in a contract
Draft clause citing this series
A starting point citing this series by name and code. Replace the bracketed terms with your contract's actual scope before use.
The [affected portion] of the Contract Price shall be adjusted using US PPI — Propane (BLS series WPU05320104), published by BLS.
Base Period: the index value published for September 2026 (or the month of contract signing, if different) is the Base Value.
Adjustment: at each Adjustment Date, the Current Value is the most recently published three-month average of the index (the Averaging Window). The Escalation Factor equals Current Value divided by Base Value.
Cap: the Escalation Factor applied under this clause shall not exceed 1.10 or fall below 0.90 (a 10% cap and floor) in any single Adjustment Date, regardless of the index's actual movement.
[Replace bracketed terms with your contract's actual affected-portion definition and adjustment-date schedule before use. This is a drafting starting point, not legal advice.]
Used in supply and delivery contracts for crop drying, fleet fuel and off-grid heating. The index follows the wholesale propane market, so a delivered-price contract needs a separate term for freight, storage and dealer margin.
Divide the current value of BLS series WPU05320104 (Propane) by its value at contract signing, then apply that ratio to the propane part of the price. A usable clause also names an averaging window, a rule for revised values and missing months, and a cap.
Let Escalake run this clause for you
Escalake tracks US PPI — Propane, applies your formula, and gives both sides a number they can confirm, no spreadsheet required.