Query: What was my body mass index in 2012?, FHIR Resource: {'resourceType': 'Observation', 'status': 'final', 'category': [{'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/observation-category', 'code': 'laboratory', 'display': 'Laboratory'}]}], 'code': {'coding': [{'system': 'http://loinc.org', 'code': '2823-3', 'display': 'Potassium [Moles/volume] in Serum or Plasma'}], 'text': 'Potassium [Moles/volume] in Serum or Plasma'}, 'subject': {'reference': 'urn:uuid:dbffb26f-e217-c238-a3a0-bd95c8f25dea'}, 'effectiveDateTime': '2016-09-02T01:57:17+05:30', 'valueQuantity': {'value': 4.16, 'unit': 'mmol/L', 'system': 'http://unitsofmeasure.org', 'code': 'mmol/L'}, 'interpretation': None}