Because of the low fuel taxes, the retail price of gasoline in the US is subject to greater changes (than outside the US) when calculated as a percentage of cost-per-unit. From 1998 to 2004, the price of gasoline was between $1 and $2 USD per U.S. gallon. After 2004, the price increased until the average gas price reached a high of $4.11 per U.S. gallon in mid-2008, then dropped approximately $2.60 per U.S. gallon as of September 2009. Recently, the U.S. has experienced an upswing in gas prices of 13.51% from Jan 31st to March 7, 2011.