| 1 - | Estimates cover urban areas only. |
| 2 - | Data refer to an earlier year than that specified. |
| 3 - | Estimates have been adjusted for arsenic contamination levels based on national surveys conducted and approved by the government. |
| .. | Data not available |
| (.) | Greater (or less) than zero but small enough to be rounded off to zero at the displayed number of decimal points |
| < | Less than |
| - | Not applicable |
| T | Total |