urn:ddi:int.naddi:f6e8508e-8596-44f6-bbc4-91996c87f5d5:1 int.naddi f6e8508e-8596-44f6-bbc4-91996c87f5d5 1 Use of DDI to document annual public-use microdata (PUMD) for ConsumerExpenditure Surveys int.example dacadd0d-4789-4bb9-8dfe-f36bcdcb32c6 1 CodeList