the number of mine workers and number of mines in Kentucky. First, increased mechanization in both Kentucky coal fields has reduced the need for labor. This has become even more pronounced with the emergence of strip mining. Secondly, acid rain regulation found in the 1990 Clean Air Act Amendment has made Kentucky coal, with its medium to high sulfur content, less desirable. That amendment requires companies to either remove the sulfur through scrubbers or switch to low-sulfur coal, found in western states like Wyoming, or submit to fines for their sulfur production. While comparably higher in sulfur content, the Eastern Kentucky coal does have a higher carbon density than Wyoming coal, so less of it has to be burned to produce the same amount of electricity, thus producing less per capita carbon dioxide emissions. Eastern coal remains widely used across the United States. The Western Coalfield has been hit much harder by acid rain regulations. Whereas about half of Eastern coal is high in sulfur content, nearly all Western coal falls into this category. In recent years the state government has been seeking to land so called "coal to gas" operations that convert coal into liquid fuels that closely resemble either natural gas or petroleum. Economic impact Employment in the coal industry followed a steady decline from the 1980s up until the 2000s, evening out at around 18,000 for the past decade. As of 2009, 18,850 Kentuckians were directly employed in the coal industry, less than 1 percent of the total workforce. Yet, when accounting for jobs indirectly involved in the industry, that number becomes much larger, nearly 73,000. This number includes education and service industry jobs in mining communities, employment from construction, transportation and manufacturing work that touches the mining industry, as well as jobs stemming from banks, law offices and engineering firms that did business with the mining industry. Coal's total economic impact is significant, with over 125.96 million tons of coal produced in 2006, making Kentucky 3rd in the nation for coal production. The state supplies 10.6% of the country with coal for power plants, giving it the nation's second-largest market share. Arguably coal's biggest economic impact has been low electric rates in Kentucky, which gives the state a competitive advantage in attracting industry, including those with heavy energy demands such as aluminum smelters and automotive plants. This has also made Kentucky one of the largest consumers