News: kids sometimes annoy other kids

Ms. Magazine reports:

A study released this month reports that 90 percent of girls between the ages of 12 and 18 reported experiencing sexual harassment. The study found that girls who had a better understanding of feminism from the media, their parents, or teachers were more likely to recognize sexual harassment. ... The most commonly reported forms of sexual harassment were unwanted romantic attention, demeaning gender-related comments, teasing based on their appearance, and unwanted physical contact.

I am wondering where they ever found kids who had not been harassed, according to that definition.