The U.S. has enough known petroleum resources to provide about 148 to 352 years of the nation's petroleum at the 2020 consumption rate. This estimate excludes some resources located offshore and in certain other locations. In 1974, Stanford University professor and bestselling author Paul Ehrlich predicted that the use of oil "to fuel industrial societies will be coming to an end" by "early in the twenty-first century" because supplies will run out. From 1974 to 2020, annual global production of crude oil rose by 51%.