<Table> Labor unions in the United States <Tr> <Th> National trade union organization (s) </Th> <Td> AFL - CIO, CtW, IWW </Td> </Tr> <Tr> <Th> National government agency (ies) </Th> <Td> United States Department of Labor National Labor Relations Board </Td> </Tr> <Tr> <Th> Primary trade union legislation </Th> <Td> National Labor Relations Act Taft - Hartley Act </Td> </Tr> <Tr> <Th> Trade union membership </Th> <Td> 16.2 million </Td> </Tr> <Tr> <Th> Percentage of workforce; </Th> <Td> <P> Total: 11.1% Public sector: 35.7% Private sector: 6.6% Demographics Age 16--24: 5.1% 25--34: 10.0% 35--44: 13.0% 45--54: 14.4% 55--64: 14.9% 65 and over: 10.4% Women: 10.5% Men: </P> 11.7% </Td> </Tr> <Tr> <Th> Standard Occupational Classification </Th> <Td> <P> Management, professional: 11.9% Service: 9.2% Sales and office: 6.5% Natural resources, construction, and maintenance: 15.3% Production, transportation, and material moving: </P> 14.8% </Td> </Tr> <Tr> <Th_colspan="2"> International Labour Organization </Th> </Tr> <Tr> <Td_colspan="2"> United States is a member of the ILO </Td> </Tr> <Tr> <Th_colspan="2"> Convention ratification </Th> </Tr> <Tr> <Th> Freedom of Association </Th> <Td> Not ratified </Td> </Tr> <Tr> <Th> Right to Organise </Th> <Td> Not ratified </Td> </Tr> </Table> <Tr> <Th> National trade union organization (s) </Th> <Td> AFL - CIO, CtW, IWW </Td> </Tr> <Tr> <Th> National government agency (ies) </Th> <Td> United States Department of Labor National Labor Relations Board </Td> </Tr> <Tr> <Th> Primary trade union legislation </Th> <Td> National Labor Relations Act Taft - Hartley Act </Td> </Tr>

What industry has the largest union membership as a percentage of total workers in the industry