pre_text: (b) Purchase Commitments with Contract Manufacturers and Suppliers We purchase components from a variety of suppliers and use several contract manufacturers to provide manufacturing services for our products. During the normal course of business, in order to manage manufacturing lead times and help ensure adequate component supply, we enter into agreements with contract manufacturers and suppliers that either allow them to procure inventory based upon criteria as defined by us or establish the parameters defining our requirements. A significant portion of our reported purchase commitments arising from these agreements consists of firm, noncancelable, and unconditional commitments. Certain of these purchase commitments with contract manufacturers and suppliers relate to arrangements to secure long-term pricing for certain product components for multi-year periods. In certain instances, these agreements allow us the option to cancel, reschedule, and adjust our requirements based on our business needs prior to firm orders being placed. The following table summarizes our purchase commitments with contract manufacturers and suppliers (in millions): We record a liability for firm, noncancelable, and unconditional purchase commitments for quantities in excess of our future demand forecasts consistent with the valuation of our excess and obsolete inventory. As of July 27, 2019 and July 28, 2018, the liability for these purchase commitments was $129 million and $159 million, respectively, and was included in other current liabilities.
table: Commitments by Period July 27, 2019 July 28, 2018
table: Less than 1 year $4,239 $5,407
table: 1 to 3 years 728 710
table: 3 to 5 years — 360
table: Total $4,967 $6,477
question: Analyse this data from a financial earnings document. What was the change in the amount of purchase commitments for commitments that were less than 1 year between 2018 and 2019?