The change in approval in percent is coded into the color of the bubbles. The bigger the bubbles, the more data the broadcast has received in the last three months. A large bubble indicates a higher confidence of a trend. Check the tooltip to see the absolute values.
If the broadcast did not exist in our database three months ago, then there is no data available at that time. A change in approval can not yet be calculated. The bubble of the broadcast is then colored in brown. Check the tooltip to see the present data available.