How was this collected? The twitter thread seems to suggest that current couples were asked what year they met and how they met, and the chart was filled out f

How was this collected? The twitter thread seems to suggest that current couples were asked what year they met and how they met, and the chart was filled out from there. If so, isn’t there some strong survivorship bias to these data, i.e., there’s a preference for longer lasting couples having met certain ways?