Analysis
NAICS 5611 is the 2022 industry group for office administrative services, part of 561 (Administrative and Support Services).
It has only one more detailed code, 561110, which covers exactly the same activities; the definition, index entries and statistics are on that page.
County Business Patterns counts 36,864 US establishments in this code in 2023, employing 550,384 people at an average annual payroll of $82,042 per employee (71st percentile of national industries). 63% of the establishments have fewer than five employees, which marks it as a small-business industry.
Between 2018 and 2023 the number of establishments grew 9% and employment rose 8%. The 2018 count used NAICS 2017, so part of a large move can come from codes being redefined rather than from businesses opening or closing.
By establishments it ranks 3rd of the 8 codes at this level within Administrative and Support Services, with 8.7% of them.