This is OPEC's official statistical bulletin. Table 9 is the most interesting, in that during the mid 1980s all the OPEC countries reserves suddenly shot up. Table 7 is also interesting, because it bellies the common conception that OPEC countries are getting absurdly wealthy on oil profits.

As oil prices remain volatile the markets do their best to forecast future prices. Unfortunately this is not an easy task. While it may appear extraordinary to outsiders one of the main problems in the oil market is the reliability of basic statistics.