Question: what was the last year ford made tractors
[{'answer': '1964', 'provenance': [{'wikipedia_id': '1078622', 'title': 'Fordson', 'start_paragraph_id': 1, 'start_character': 302, 'end_paragraph_id': 1, 'end_character': 306, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1078622', 'title': 'Fordson', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 384, 'bleu_score': 0.9716239638199891, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7444452717611976816}, 'section': 'Section::::Abstract.'}]}]