minHealthyPercentage

Specifies the minimum percentage of the group to keep in service, healthy, and ready to use to support your workload to allow the operation to continue. The value is expressed as a percentage of the desired capacity of the Auto Scaling group. Value range is 0 to 100.

If you do not specify this property, the default is 90 percent, or the percentage set in the instance maintenance policy for the Auto Scaling group, if defined.