By default and recommended for production use, ISE suppresses repeated failed and successful authentications. If that is what you have, please use an external syslog target to capture such info.
If you have turned off all the suppressions (not recommended beyond lab testing), then run RADIUS authentications reports under ISE Admin web menu > Operations > Reports > Reports) with your criteria, export the results to a repository, and then use an external application (e.g., MS Excel) to process them further.
