Given above stats, the weighted average adult literacy should be above 70%. But why the bottom chart (1992) is still showing India as dark red (30%-50%)?
Secondly, it's fine to compare China and Columbia but you gotta be careful when you try to draw a conclusion based on that comparison, as they're not truly comparables. It's much more difficult for a country with large population to achieve the same literacy level as for a small country.