What percentage of adolescent seniors in high school think it is okay for teenagers to have sexual intercourse?

70%

Explanation:

The vast majority represented by 70% of adolescent seniors in high school share the opinion that it is all right to have sexual intercourse at their age.

On the one hand, biologically adolescent seniors have fully entered sexually active age, while on the other hand they developed higher psychological and emotional maturity than adolescent juniors to handle impact that comes with sexual intercourse, and also involve in it responsibly, for example by using protection.