Question: when did bruno mars win his first grammy
[{'answer': '2011', 'provenance': [{'wikipedia_id': '31491748', 'title': 'List of awards and nominations received by Bruno Mars', 'start_paragraph_id': 2, 'start_character': 847, 'end_paragraph_id': 2, 'end_character': 851, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]