Question: how many nfl games were played in london
[{'answer': '21', 'provenance': [{'wikipedia_id': '15558076', 'title': 'NFL International Series', 'start_paragraph_id': 2, 'start_character': 397, 'end_paragraph_id': 2, 'end_character': 399, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '15558076', 'title': 'NFL International Series', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12470604311221316454}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '15558076', 'title': 'NFL International Series', 'section': 'Section::::Abstract.', 'start_paragraph_id': 2, 'end_paragraph_id': 2, 'meta': {'evidence_span': ['Initially, all games in the International Series were held in London. Wembley Stadium was the exclusive home stadium for International Series games from 2007 to 2015 and will continue to host at least two NFL games through at least 2020; beginning in 2016, the series began expanding to more stadiums, first to Twickenham Stadium in London (20162017) and to Estadio Azteca in Mexico City (20162021) and eventually to Tottenham Hotspur Stadium in London (20192027), with possible future plans to expand the series to Germany and/or Canada.', 'continue to host at least two NFL games through at least 2020; beginning in 2016, the series began expanding to more stadiums, first to Twickenham Stadium in London', 'host at least two NFL games']}}]}]