The Census of Agriculture 1979 only covered the Portuguese Mainland. This major statistical operation followed the FAO guidelines for world agriculture census of 1980 and included, as far as possible, the European legal regulations.  RAC 79 provided users with comparable results to the previous census of agriculture – 1968.
The objectives of RAC 79 were the following:
- to provide data on the farms' structure in the mainland
- to provide data on agricultural area, livestock animals, machinery and equipment, farm labour force and agricultural population;
- to provide data detailed by the geographical localization;
- to obtain the sampling frame for specific surveys on agriculture;
- to provide  information for the political measures.