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, Total Expense for Business and Secretarial Schools, All Establishments, Employer Firms (DISCONTINUED SERIES) [EXPEF61141ALLEST], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/EXPEF61141ALLEST/, August 31, 2015.