Question: when was the euro introduced as legal currency on the world market
[{'answer': '16 December 1995', 'provenance': [{'wikipedia_id': '9472', 'title': 'Euro', 'start_paragraph_id': 5, 'start_character': 42, 'end_paragraph_id': 5, 'end_character': 58, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '9472', 'title': 'Euro', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 311, 'bleu_score': 0.9611463610973231, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 329886248882632198}, 'section': 'Section::::History.:Introduction.\n'}]}]