| Irrigated area | Year | Irrigated area | Year |
| 75 | 1990 | 86 | 1955 |
| 75 | 1995 | 72 | 1961 |
| 75 | 1998 | 64 | 1966 |
| 71 | 2000 | 68 | 1970 |
| 81 | 2005 | 87 | 1973 |
| 61 | 2010 | 74 | 1979 |
|
|
| 79 | 1984 |