U.S. Bureau of Labor Statistics (QCEW open-data API, Compiled tables: QCEW annual averages 2019-2021 for NAICS 532, 5321, 5322, 5323, 5324 (national, private); QCEW quarterly 2020 Q1-2021 Q3 for NAICS 532; CES series CES5553200001 2020-2021 (Sept. 27, 2026) (Ex. SEC-22-030)
