A little deceiving because the data uses kids who parents did or did not go to college.
Far more people attend college than say 30 years ago. One reason is jobs that did not require college degrees or associate degrees now do.
Second it is much more easier to attend college now with easier access to junior college and online schools. One main reason for this is college education is big business for schools. Aka for profit education.
Finally a parent attending college does not mean they completed college. But it checks off their child as being a second generation college student once that child attends college.
So as a person you can attend college for a semester and drop out. Get married have a child and never attend college again. But if your child attends college the child will be a second generation college student and not a first generation.
30% of Americans have college degrees