| Year | Internal flow (million m3) | Inflow of surface and groundwater from neighbouring countries (million m3) |
|---|---|---|
| 1981 | 41033 | 8329.714 |
| 1982 | 47121 | 8383.332 |
| 1983 | 35207 | 6919.876 |
| 1984 | 34092 | 7658.364 |
| 1985 | 49796 | 7638.988 |
| 1986 | 42229 | 9212.834 |
| 1987 | 45033 | 9764.784 |
| 1888 | 53785 | 13093.84 |
| 1989 | 45599 | 9566.082 |
| 1990 | 49001 | 8291.866 |
| 1991 | 36022 | 6345.848 |