Appointment arrival chart only shows hours with scheduled appointments, not all hours in the day

Hello, I have attached a screenshot of the widget I have built. I am trying to capture the number and frequency of appointments in a day for a clinic. As you can see in the screenshot, when there isn't an appointment, the chart doesn't show the hours. For example, on 9/8 there is an appointment at 12 pm and the next one isn't until 2:30 pm. Is there a way that the chart can still show the hours in between that gap where there isn't an appointment?