From different locations. I do not believe any location has seen an 84% increase. National Average is ~38%
Central Valley of California here...gasoline up 47.6% since November 2006.
I only included the image because I can personally attest to purchasing gasoline in late January for $1.99/gallon at Speedway in Grand Rapids, MI. That price was widespread in th area. Yesterday, I drove past Speedway with the price on the sign being $3.65. And again that price was widespread in the area. I confess that I'm no mathematician or statistician, but I can certainly see that's not very far away from a $2 increase over a $2 price in only 3-4 months.
Also, in November I bought an older Subaru to commute in. The Durango I so enjoy is parked in the driveway, except when the whole family has to go somewhere (the children's car seats don't fit in the Subaru). When I first started filling the car up, I was pleased that it only took about $20. Now just a few months later, it takes about $35. That's a $15 increase on a $20 purchase ... not terribly far from double in a relatively short time period. At twice a week, that can be an additional $120+ per month burden on a family that is already struggling in the face of double job losses, a rising standard of required credentials/qualifications in our previous careers and the sacrifices that are part of retraining to enter the ministry.
Again, my apologies, I understand its probably useful in other areas across the country, but I personally don't find the national average terribly indicative of or helpful to local circumstances because Michigan really isn't the national average ... for example, compare our unemployment rate to the national average.