The abbreviation of a state is entered in this element. The basis is ISO 3166-1
for the assignment of two capital letters [1] to a state.
<xs:simpleType name="stringISO3166Type">
<xs:restriction base="xs:string">
<xs:pattern value="[A-Z]{2}"/>
</xs:restriction>
</xs:simpleType>
The element StringISO3166 is configured to hold exactly two uppercase letters.