Source: US. Bureau of Economic Analysis
Release: Gross Domestic Product by Industry
According to the source, gross output is a measure of an industry's sales or receipts, which can include sales to final users in the economy (GDP) or sales to other industries (intermediate inputs).
US. Bureau of Economic Analysis, Gross Output of Private Industries: Finance, Insurance, Real Estate, Rental, and Leasing (Chain-Type Price Index) [GOPIPFIRL], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/GOPIPFIRL, December 2, 2016.