Figure 22. Natural gas proved reserves. At the end of 2000, natural gas proved reserves were estimated to be 5,304 trillion cubic feet. The six countries with more reserves than the United States (with 167 TCF) are Russia (1,700 TCF), Iran (812 TCF), Qatar (394 TCF), Saudi Arabia, and U.A.E. Source: BP Statistical Review of World Energy, June 2001.