Table of Content Twelve Months Ended December 31, 2022 United States and Canada Other Countries Total Revenue: IHT $ 412,661 $ 9,901 $ 422,562 MS 296,151 121,495 417,646 Total $ 708,812 $ 131,396 $ 840,208 Twelve Months Ended December 31, 2023 Non-Destructive Repair and Maintenance Evaluation and Testing Heat Treating Other Total Services Services Revenue: IHT $ 343,713 $ 275 $ 59,399 $ 26,172 $ 429,559 MS — 429,480 702 2,874 433,056 $ 343,713 $ 429,755 $ 60,101 $ 29,046 $ 862,615 Total Twelve Months Ended December 31, 2022 Non-Destructive Repair and Maintenance Evaluation and Testing Heat Treating Other Total Services Services Revenue: IHT $ 336,821 $ 180 $ 61,526 $ 24,035 $ 422,562 MS — 413,424 276 3,946 417,646 $ 336,821 $ 413,604 $ 61,802 $ 27,981 $ 840,208 Total For additional information on our reportable operating segments and geographic information, refer to Note 17 - Segment and Geographic Disclosures. Remaining performance obligations. As permitted by ASC 606, Revenue from Contracts with Customers, we have elected not to disclose information about remaining performance obligations where (i) the performance obligation is part of a contract that has an original expected duration of one year or less or (ii) when we recognize revenue from the satisfaction of the performance obligation in accordance with the right-to-invoice practical expedient, which permits us to recognize revenue in the amount to which we have a right to invoice the customer if that amount corresponds directly with the value to the customer of our performance completed to date. As most of our contracts with customers are short-term in nature and billed on a time and material basis, there were no material amounts of remaining performance obligations as of December 31, 2023 and 2022. 4. ACCOUNTS RECEIVABLE A summary of accounts receivable as of December 31, 2023 and 2022 is as follows (in thousands): December 31, 2023 2022 Trade accounts receivable $ 151,316 $ 160,572 Unbilled revenues 33,607 31,379 Allowance for credit losses (3,738) (5,262) Accounts receivable, net $ 181,185 $ 186,689 40