Question: when did the vikings start using the skol chant
[{'answer': '1961', 'provenance': [{'wikipedia_id': '3323728', 'title': 'Skol, Vikings', 'start_paragraph_id': 1, 'start_character': 160, 'end_paragraph_id': 1, 'end_character': 164, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3323728', 'title': 'Skol, Vikings', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 256, 'bleu_score': 0.8780099567239781, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9933554990858785633}, 'section': 'Section::::Abstract.'}]}]