It's an upward trend, though, even after you correct for inflation, because the supply is exhaustible. That's what happens when you've got an exhaustible commodity. How fast it goes up depends on how fast you use it. Right now, we are using it very fast, primarily because of the exponential economic growth in India, China, and Russia.
You can find some other points in history where the price was higher after correcting for inflation. One of those was after the OPEC oil squeeze in the 70's. However, I don't think that I would want to relive that. Comparing the current situation to that, and thinking that it proves things are pretty good, is just nuts. That was the blackest economic situtation since the Great Depression. It's not saying much to say, "well, it was worse then."
The price of gasoline is influenced much more by political and economic factors than anything else. And I really don't see a long term trend in gas prices. Five years ago the price was lower than it was in 1970 even BEFORE the Arab oil embargo.