Question: when did the words under god get added to the pledge of allegiance
[{'answer': 'Flag Day 1954'}, {'provenance': [{'wikipedia_id': '59581', 'title': 'Pledge of Allegiance', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 533, 'bleu_score': 0.603657145882859, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8445493701361480427}, 'section': 'Section::::Abstract.'}]}]