Fuels comprise the commodities in SITC section 3 (mineral fuels, lubricants and related materials). Limitations and exceptions: Previous editions contained data based on the SITC revision 1. Data for earlier years in previous editions may differ because of the change in methodology. Concordance tables are available to convert data reported in one system to another. Statistical concept and methodology: The classification of commodity groups is based on the Standard International Trade Classification (SITC) revision 3.