2. Increase in overall supply - the oil companies (which own the refineries for the vast proportion) took many refineries offline (for "maintenance") to artificially bump up prices and destroyed the global economy in so doing, so they stopped doing that.
Saying that oil companies are closing whole refineries to lower the demand is far from reality: on average, if you look at the worldwide uptime in downstream (the uptime of refineries), we are close to 95% (I don't have the exact figure handy). Uptimes in upstream are worse, as you have to deal with typhoons, looters and kidnappers.
But in France for example, oil companies have delayed investements in new capacities for refining diesel, and have caused a noticeable bump of the price (I'm not discussing the impact of state taxs on this, but they are interesting). But greedyness is not the ony factor that comes into play: back in 1998-2000, refining companies were losing money doing their job. When you take into account that it requires 5 years to design and install a new unit (costing from 50M to 1B$), or 10 years for a whole refinery, you are careful when you take your decision.
That said, according to some leftists, three years of profit from Total are enough to end starvation on Earth. But that's another matter.
UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things. -- Doug Gwyn