In 1977 there were about 300 offshore rigs (semi-submersibles, jack-ups, and drill ships) in service worldwide and nearly 2 000 supply ships were required to support them.
Ngo 1977 kwakusekukho isinxibo samanxweme esiyi 300 (Ukuntywiliseka okungagqibelelanga, isixhobo esiphakanyiswayo inqanawa ezihanjiswayo) kwinkonzo kwilizwe ngobubanzi kufutshane ne 2000 yenqanawa ezixhobisayo eziyimfuneko ukuhlwayela elunxwemeni namaqhinga emveliso.