Who chose the bins? As is, the bins produce a bimodal distribution which probably isn't accurate. By definition, the bins should all be the same size within the area of interest. I guess in this case, judging by bin size, the area of interest is the teen/tween population? If I were to make the bins, I would make 5 year bins from 0 to 100. That way I get a clearer picture of the true distribution. Then bimodal distributions (or other statistical anomalies) would actually be of interest.