Pivot table time by hour averages (for occurrences not time)

I am creating an excel pivot table that takes avg times per day so that I can plot in a bar chart. I would like to group each time by hour and calculate how many instances where those times appear (per hour). The column/variable of interest is "Arrival Time." I have put the times in the rows (In pivot) but when I attempt to put the times in the values and average them, excel won't calculate the average instances of those times. I would like the data to be pulled from the sheet "Admissions Long Sheet" and the pivot table to be placed in the sheet titled "TOD Distribution" I have attached a sample workbook with deidentified information. If anyone can help with this, it will be greatly appreciated.