Because the addressee/salutation ID number is only used during import, the field is not available to export from the Export module. Instead use the "create an import file" functionality located in Administration, Import. To export the primary addressee/salutation ID number, select the Constituent import type. To export an additional addressee/salution ID number, select the Additional Addressee/Salutation import type. Both of these import types are located under the Consituent node.