International Financial Statistics provides the world oil price series (line number 00176AAZZF: the simple average of U.K. Brent (light), Dubai
(medium), and West Texas Intermediate) since the early 1950s, monthly, quarterly, and annually. For the data source, see page 6 of IFS World & Country Notes, September 2006.
Used by Collier and Goderis (2007).
International Energy Annual (Table 7.1) also provides annual crude oil prices for major oil producing countries since 1980.