According to an online survey by feminist NGO Think Olga, some 86 percent of women in Brazil have been groped at bars or clubs.

To highlight the problem, ad agency Ogilvy sent three women wearing a touch-sensitive dress to a nightclub in São Paulo, Brazil, to record how often they were groped over the course of almost four hours in total.

The agency—which conducted the experiment as part of a campaign by Schweppes—asked men on a night out whether they thought women really faced widespread sexual harassment in bars. Some men included in an Ogilvy video said they didn’t think women experience major problems with harassment.

But data collected by the touch-sensitive dress painted a different picture. Researchers found the women were touched 157 times over three hours and 47 minutes—that’s more than 40 times per hour.