Regional classification | 1961-1990 | 1966-1995 | 1971-2000 | 1976-2005 | 1981-2010 | 1986-2015 |
Mildly suitable area | 281 | 224 | 227 | 225 | 247 | 236 |
Moderately suitable area | 343 | 286 | 286 | 276 | 289 | 273 |
Fully suitable area | 803 | 773 | 775 | 777 | 774 | 750 |