High school kids are taking more online classes

The UCLA Higher Education Research Institute conducts annual surveys of incoming college freshmen. There are many interesting questions, but since I teach an undergraduate course on Internet literacy, and education applications and services are increasingly important, I focus on two questions in particular:

1. Have you used an online instructional website (e.g., Khan Academy, Coursera) as assigned for a class?
2. Have you used an online instructional website (e.g., Khan Academy, Coursera) to learn something on your own?

The following table shows the percent of incoming freshmen who answered frequently or occasionally:

Three things strike me in looking over these results:

1. Students are not waiting for their schools -- they are taking online classes on their own.
2. Students attending historically black colleges are doing more online study than others.
3. Online classes are growing in popularity among students working on their own and as assigned work.

How would you explain these observations? Do you expect them to continue?
(I also wrote a post after last year's freshman survey).

My grandson took a break from Minecraft to complete
Khan Academy algebra 2 before starting high school.