Question: when was the last time mount st helens erupted before 1980
[{'answer': '1857', 'provenance': [{'wikipedia_id': '36649', 'title': 'Mount St. Helens', 'start_paragraph_id': 28, 'start_character': 628, 'end_paragraph_id': 28, 'end_character': 632, 'bleu_score': 1.0, 'section': 'Section::::Geologic history.:Kalama and Goat Rocks eruptive periods.\n'}]}, {'provenance': [{'wikipedia_id': '36649', 'title': 'Mount St. Helens', 'start_paragraph_id': 28, 'start_character': 0, 'end_paragraph_id': 28, 'end_character': 933, 'bleu_score': 0.9394248920800681, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17577412680921045165}, 'section': 'Section::::Geologic history.:Kalama and Goat Rocks eruptive periods.\n'}]}]