OPEC is the the Organisation of the Petroleum Exporting Countries was set up in 1960. It has 12 member countries that are known as a cartel when it comes to oil production. These countries are:-
Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates & Venezuela
The daily oil production in barrels per day:-
Saudi Arabia 11,530,000
This totals: 37,405,000 barrels per day from OPEC
Now global total oil production is 91,331,000 barrels per day
37,405,000 / 91,331,000 = 40%
OPEC accounts for just over 40% of Global Oil Production. This really is Big Oil.