Total recoverable reserves of coal around the world are estimated at 909 billion tons—reflecting a current reserves-to-production ratio of 129 years. Historically, estimates of world recoverable coal reserves, although relatively stable, have declined gradually from 1,145 billion tons in 1991 to 1,083 billion tons in 2000 and 909 billion tons in 2008. Although the decline in estimated reserves is sizable, the large reserves-to-production ratio for world coal indicates that sufficient coal will be available to meet demand well into the future. (emphasis mine)Above this statement on the same page was this graph
The growth rate for coal consumption is uneven, averaging 1.1 percent per year from 2007 to 2020 and 2.0 percent per year from 2020 to 2035.