[SCH-EUSR-14] Only allowed subset types MUST be used.
SCH-EUSR-14
/eusr:EndUserStatisticsReport
count(eusr:Subset[normalize-space(@type) !='PerDT-PR' and normalize-space(@type) !='PerDT-PR-EUC' and normalize-space(@type) !='PerDT-EUC' and normalize-space(@type) !='PerEUC']) = 0