From Jan 2017 to Sep 2026 the index went from 136.3 to 197.7, a change of +45.0%.
Highest reading in that period: 203.1 in Jul 2026. Lowest: 119.5 in Nov 2021.
Largest one-month rise: +19.2% in Jun 2022. Largest one-month fall: -18.9% in Nov 2019.
For a clause that resets its base every year, a 10% cap or floor would have limited the adjustment in 2 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 — Unprepared Bituminous Coal and Lignite (Utility Sold) (BLS series WPU05130101), 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.]
Split the contract by asset type: solar, wind, transmission, substations, or water. Transformers (PCU335311335311) and switchgear (PCU335313335313) have real, live BLS price indices. Solar, wind, and power line construction do not, so those need a weighted input composite instead.
Let Escalake run this clause for you
Escalake tracks US PPI — Unprepared Bituminous Coal and Lignite (Utility Sold), applies your formula, and gives both sides a number they can confirm, no spreadsheet required.