Question: when was the safety car introduced in formula 1 races
[{'answer': '1973 Canadian Grand Prix', 'provenance': [{'wikipedia_id': '1346752', 'title': 'Safety car', 'start_paragraph_id': 15, 'start_character': 84, 'end_paragraph_id': 15, 'end_character': 108, 'bleu_score': 1.0, 'section': 'Section::::Formula One.:History.\n'}]}, {'provenance': [{'wikipedia_id': '1346752', 'title': 'Safety car', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 479, 'bleu_score': 0.976327165973018, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5269249851882796494}, 'section': 'Section::::Formula One.:History.\n'}]}]