Within 2 years after October 11, 1996, and at least once every 2 years thereafter, the Secretary of Commerce shall prepare and submit to the Congress and the Secretary a report examining whether operation of the Council, in conjunction with the cumulative effects of market changes and Federal programs, has had an effect on propane consumers, including residential, agriculture, process, and nonfuel users of propane. The Secretary of Commerce shall consider and, to the extent practicable, shall include in the report submissions by propane consumers, and shall consider whether there have been long-term and short-term effects on propane prices as a result of Council activities and Federal programs, and whether there have been changes in the proportion of propane demand attributable to various market segments. To the extent that the report demonstrates that there has been an adverse effect, the Secretary of Commerce shall include recommendations for correcting the situation. Upon petition by affected parties or upon request by the Secretary of Energy, the Secretary of Commerce may prepare and submit the report required by this section at less than 2-year intervals.