The default option for Monitor I data gathering is NOESS. Therefore, you must specify the ESS Monitor I gatherer option if you want to get data for this report.
REPORTS(ESS)This report is also available in XML output format. Topic How to work with Postprocessor XML reports in the z/OS RMF User's Guide provides all required information on how to produce and view XML reports.
Example URL for the DDS API:
http://ddshost:8803/gpm/rmfpp.xml?reports=ESS