How many tariff codes have a bts retail price of 2.553p/min?
{'header': ['Scheme', 'Tariff code', 'BTs retail price (regulated)', 'Approx premium', 'Prefixes'], 'page_title': '', 'section_title': '', 'caption': '', 'rows': [['Pence per call, fixed at all times', 'ff15', '5.10p/call', '7p/call', '0871, 0872'], ['Pence per call, fixed at all times', 'ff28 NTS', '8.50p/call', '10p/call', '0871, 0872'], ['Pence per call, fixed at all times', 'ff0 PRS', '8.60p/call', '10p/call', '0871, 0872'], ['Pence per minute, fixed at all times', 'g21', 'geographic rate or inclusive', 'nil', '030, 033, 034, 037'], ['Pence per minute, fixed at all times', 'g22', '0.425p/min', '2p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g8', '0.851p/min', '2p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g27', '1.277p/min', '3p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g9', '1.702p/min', '4p/min', '0843, 0844'], ['Pence per minute, fixed at all times', '(no code)', '2p/min or inclusive', '2p/min', '0845 only'], ['Pence per minute, fixed at all times', 'g28', '2.128p/min', '3p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g10', '2.553p/min', '4p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g11', '3.404p/min', '5p/min', '0843, 0844'], ['Pence per minute, fixed at all times', 'g6 and p27', '4.255p/min', '7p/min', '0843, 0844, 0871, 0872'], ['Pence per minute, fixed at all times', '(no code)', '8p/min or inclusive', '~10p/min 0p/min', '0870 only']]}