Different areas of the US have different needs. Some States are more opulent, so gas is higher, while less opulent, are lower. In Michigan is are around 2.89 or slightly lower.
Fuel prices have not changed that much. Since being in China for 14 years, the price has only gone up about $1.00
Funny that over 14 years ago Unleaded was higher than Diesel, but is now the exact opposite.