Oil is a valuable commodity for many countries, including some you might not expect. The price of oil was rising following the rollout of COVID-19 vaccines but the arrival of the Delta variant prompted the Organization of the Petroleum Exporting Countries (OPEC) to scale back its forecast for oil demand at the end of 2021. With the forecast set to rise to pre-pandemic levels this year, read on as we count down from the 30th largest producer to the world leader, based on 2020 data from BP’s Statistical Review of World Energy 2021.