[SCH-EUSR-21] The number of SendingOrReceivingEndUsers MUST be greater or equal to the number of ReceivingEndUsers
SCH-EUSR-21/eusr:EndUserStatisticsReportxs:integer(eusr:FullSet/eusr:SendingOrReceivingEndUsers) >= xs:integer(eusr:FullSet/eusr:ReceivingEndUsers)