Manufacturers in this industry focus on transforming petroleum and coal into functional products. Demand is largely driven by the consumption of fuel and the building and maintenance of roads and structures. Transportation and construction industries are important to monitor. The most defining feature of the industry is its substantial fluctuations in annual revenues caused by extreme sensitivity to changing market prices of crude oil. With high dependencies on volatile industry sectors, petroleum and coal products manufacturing must focus on efficient operations in order to promote productivity and maintain profit stability.