Estimate: 2030. About 15 years for this to become a truism. Amazingly fast given the magnitude of the change.
In the 19th and 20th century, illiteracy was seen as an inability to read or write. Illiteracy damaged your economic prospects and your ability to function in society as a whole.
With the arrival of the Internet (and the world of knowledge it connects you to), being illiterate is increasingly being seen as an inability to learn on your own.
Learning is now a continuous lifelong activity and with the Internet available, it's largely accomplished using a self-service approach. When you want to find something out you can usually find it on the Internet, or if you need to learn a new skill, you can usually find a course on the Internet to learn it and experts to help you out.
With the arrival of cognitive machines (using "deep learning" and other model free methods), our definition of illiteracy will change again. Based on what I see, illiteracy will increasingly be seen as an inability to teach, coach, and train machines that learn.
From teaching a car to drive itself to training to evaluate an insurance claim to coaching a bot to spot a person with a concealed weapon, you will find yourself in charge of helping bots learn about the world.