scalingAdjustmentType
The type of adjustment to make to a fleet's instance count.
ChangeInCapacity -- add (or subtract) the scaling adjustment value from the current instance count. Positive values scale up while negative values scale down.
ExactCapacity -- set the instance count to the scaling adjustment value.
PercentChangeInCapacity -- increase or reduce the current instance count by the scaling adjustment, read as a percentage. Positive values scale up while negative values scale down.