| $ | US dollar |
| ¥ | Japanese yen |
| £ | Pound sterling |
| € | Euro |
| mb/d | Million barrels per day |
| . . | Data not available |
| 0 | Nil or negligible |
| – | Irrelevant |
| . | Decimal point |
| I, II | Calendar half-years |
| Q1, Q4 | Calendar quarters |
| Billion | Thousand million |
| Trillion | Thousand billion |
| s.a.a.r. | Seasonally adjusted at annual rates |
| n.s.a. | Not seasonally adjusted |