Question: when did roger federer first play at wimbledon
[{'answer': '1998', 'provenance': [{'wikipedia_id': '262376', 'title': 'Roger Federer', 'start_paragraph_id': 1, 'start_character': 422, 'end_paragraph_id': 1, 'end_character': 426, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '262376', 'title': 'Roger Federer', 'start_paragraph_id': 19, 'start_character': 0, 'end_paragraph_id': 19, 'end_character': 686, 'bleu_score': 0.9481043341304051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14417135805909783997}, 'section': 'Section::::Tennis career.:Pre–1998: Junior years.\n'}]}]