curl -XPOST "http://localhost:8080/core/api/v2/observation" -d '
{
     "select": [
         "date",
         "value",
         "variable",
         "entity"
     ],
     "entity": {
         "expression": "country/USA<-containedInPlace+{typeOf:State}"
     },
     "variable": {
         "dcids": [
             "Count_SubsidizedHousingUnit"
         ]
     },
     "date": "2023-12-31"
}
'

{"byVariable":{"Count_SubsidizedHousingUnit":{}}}

{"byVariable":{"Count_SubsidizedHousingUnit":{"byEntity":{"geoId/40":{"orderedFacets":[{"facetId":"4243125145","observations":[{"date":"2023-12-31","value":53562}],"obsCount":1,"earliestDate":"2023-12-31","latestDate":"2023-12-31"}]},"geoId/41":{"orderedFacets":[{"facetId":"4243125145","observations":[{"date":"2023-12-31","value":57113}],"obsCount":1,"earliestDate":"2023-12-31","latestDate":"2023-12-31"}]},"geoId/02":{"orderedFacets":[{"facetId":"4243125145","observations":[{"date":"2023-12-31","value":7962}],"obsCount":1,"earliestDate":"2023-12-31","latestDate":"2023-12-31"}]}, ... }}