Literacy is one of the demographics in Civilization 5. How is it calculated? How do you compare two civilizations via this statistic? Are you able to tell how advanced a civ is compared to you by comparing your relative Literacy ratings?
It's the percentage of the total technologies you've researched, as long as you have writing, otherwise it's always 0. Note that what follows is not my research, I found this on the CivFanatics forums:
Since "Future Tech" never gets fully researched, you can never reach 100% literacy.