Source:
International Labour Office (ILO): Global estimates of modern slavery: forced labour and forced marriage. 2017
--> Sector of forced labour exploitation: Sectoral distribution of victims of forced labour exploitation.
Note:
These figures are based on cases of forced labour exploitation where industry was reported. Information on the industry was available for 65% of total cases of forced labour exploitation; and with the exception of begging, categories are based on the International Standard Industrial Classification of All Economic Activities, Rev.4 (1-digit level). For further detail and explanation see United Nations Statistics Division (https://unstats.un.org/unsd/cr/registry/regcst.asp?Cl=27).
Link:
http://www.ilo.org/wcmsp5/groups/public/---dgreports/---dcomm/documents/publication/wcms_575479.pdf