<xs:simpleType name="AmountOfSubstancePerAmountOfSubstanceUom">
  <xs:restriction base="eml:UomEnum">
    <xs:enumeration value="%">
      <xs:annotation>
        <xs:documentation>percent</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="%[molar]">
      <xs:annotation>
        <xs:documentation>percent [molar basis]</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="Euc">
      <xs:annotation>
        <xs:documentation>euclid</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="mol/mol">
      <xs:annotation>
        <xs:documentation>mole per mole</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="nEuc">
      <xs:annotation>
        <xs:documentation>nanoeuclid</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ppk">
      <xs:annotation>
        <xs:documentation>part per thousand</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ppm">
      <xs:annotation>
        <xs:documentation>part per million</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
  </xs:restriction>
</xs:simpleType>