See Fact #915: March 7, 2016 Average Historical Annual Gasoline Pump Price, 1929-2015 from the U. S. Department of Energy.
They have a timeline chart and a table of the price each year and then the price adjusted for inflation (put in 2015 dollars). The average price over the whole time period is $2.20 (I just added up all the prices and divided by 87 and it is adjusted for inflation). In 2015 it was $2.45. So we were not too far above that last year. The lowest price ever for a single year, adjusted for inflation, was $1.47 in 1998. The next lowest was $1.59 in 1972. The highest was $3.80 in 2012.
Here is the timeline chart