For further information, please refer to the US Census Bureau's Annual Services release, online at http://www.census.gov/services/.
Source: US. Bureau of the Census
Release: Annual Services Survey
US. Bureau of the Census, Purchased Repairs and Maintenance for Architectural, Engineering, and Related Services, All Establishments, Employer Firms [EXPPRMEF5413ALLEST], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/EXPPRMEF5413ALLEST/, July 6, 2015.