This percentage is a number between 0 and 100 that informs the user about the progress of an installation. It should be used whenever an update activity takes longer and the user should be informed about the completion. If the state machine is in Idle State it shall have the value 0. In case of an error the last value should be kept until the Resume is called.
Note: This information is for the user only. It shall not be used to detect completion of the installation.