I used Matplotlib to create a histogram of ridership by age group and hour of day for July 2017(Figure 3). Please see caption below for more details on construction.  Bars with red tops are hours with more young riders; bars with blue tops are hours with more older riders. Except for the early commuting hours of 5 A.M. - 8 A.M., younger riders outnumber older riders. That difference is especially apparent in the proportions for the early-morning hours (0-4, at left), though the overall number of trips is low.