Exhibit

We have audited the consolidated financial statements included in the Form 10-K and issued our report thereon dated February 27, 2018. Note 1 to the financial statements describes a change in accounting principle pertaining to the date the Company's annual impairment test is performed for goodwill associated with its U.S. Services and Manufacturing reporting units from December 31 to October 31. It should be understood that the preferability of one acceptable method of accounting over another for a change in the annual impairment testing date for goodwill has not been addressed in any authoritative accounting literature, and in expressing our concurrence below we have relied on management’s determination that this change in accounting principle is preferable. Based on our reading of management’s stated reasons and justification for this change in accounting principle in the Form 10-K, and our discussions with management as to their judgment about the relevant business planning factors relating to the change, we concur with management that such change represents, in the Company’s circumstances, a change to a preferable accounting principle in conformity with Accounting Standards Codification 250, Accounting Changes and Error Corrections.