For each country studied, the analysis is divided into two parts: aggregate fossil fuel consumption, and a system of fuel shares. Two possible models are developed for aggregate energy consumption: the first includes an exogenous trend in energy intensity while the second attempts to endogenize this trend. Quarterly data from 1978-90 were used in estimation. Full details of the econometric analysis including results and significance statistics are available in Boone et al [6] and Hall et al [11].