A lot of this just comes down to supply and demand. Speculation on futures across a geography influences retail costs in what seems like an unpredictable way to the end consumer.
I'd wonder if the year to year numbers really look all that different. It's a good question to ask before calling conspiracy.
well first i heard it was attributed to a broken pipeline out west
then iran announced it had a sh1tload more oil than previously thought, so i had the idea that this miscalculation would send the price lower
but it's been climbing ever since