Nations which are largest oil producers

  I was thinking that highest oil producing countries are gulf countries.

They have got rich by selling petrol.... 

But I was wrong.  Gulf countries are not the highest oil producers   !!!! 

Highest oil producing countries are  - - - 

1.   United States of America 

2.  Saudi Arabia 

3.  Russia 

4.  China 

5.  Canada 

6. Iraq