The rate below your currently available rate is the median rate of the properties in your competitive set; the median is the middle value of a range of values and is different from the average. If you, for example, have the following range of rates "90, 113, 150", then 113 is the median value and 117 the average. The system uses the median instead of the average rate because the average may significantly be influenced by extremely low or high rates (which could create a false representation of the market demand).
By clicking on Comp. Set Rates that you can find in the sidebar on the right, you can see the individual rates of the properties in your competitive set up until 60 days from the current date.